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Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

Hi there! I have a new Samsung Galaxy A50 and have some problems with the WiFi at home (2x UniFi AP-AC-PRO). When I get out of range of the access points, it automatically disconnects and goes to 4G. When I get back in range it doesn't reconnect automatically. I have to manually turn off the WiFi and turn it back on again on the phone to reconnect.

 

I have two UniFi AP-AC-PRO's with firmware 4.0.30.10217. One is downstairs and one is upstairs (we have 3 floors). Changing between the two access points works great. The issue only happens when I get out of range of both AP's and get back in range.

 

Some extra information:

 -When mobile data (4G) is on, I only have to step outside for it to lose connection to the AP's and switch to 4G. When I turn my mobile data off, it takes a lot longer for the AP's to lose connection. It also doesn't reconnect in this case.

- I tried getting out of range and then standing next to both AP's. It doesn't reconnect to both of them.

- I reactivated the WiFi on my internet provider's router and I don't have the issue with that router. So it seems to be something with the UniFi network. Also didn't have this problem at my parents' house (they don't have a UniFi network).

- I didn't have this problem with my old phone (Samsung Galaxy S6) and my Macbook. My girlfriend also doesn't have any issues with her S7, Macbook and iPad.

- I've called with Samsung support and did all the things they adviced (reboots, forgetting network, resetting network settings, restarting in safe mode, etc.). That didn't help. They said I should maybe send the phone back and get a replacement. The strange thing however is that I don't have this problem with other AP's, so I first want to see if I can fix it by changing something in my network.

- I already changed the channels on both AP's, set the transmit power to medium (2G) and high (5G). Also tried low and medium. No results. Before I did this it also disconnected while being in range (it was set to Auto before).

- I manually updated the firmware to 4.0.30.10217 to see if that would fix my problem. It sadly didn't.

 

I can still try two things:

1) My mother has the same phone. I can ask her to come over to see if she has the same problem.

2) My brother also has a UniFi network. I can see if I have the same issue at his place. My sister in law also has some problems with her Samsung Galaxy S6 disconnecting automatically, but I think that's a different issue.

 

I've added the system config to the post. Anyone else who has this problem? Or any ideas on how to solve this or what might be causing this?

 

Thanks! Man Happy

systemConfig.png

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New Member
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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

After a few days everything is still working great! So the problem has been fixed for the Samsung Galaxy A50. Simply update it to the newest version. Man Happy

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New Member
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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

[ Edited ]

Update: My mother came by with her Samsung Galaxy A50 and has the exact same issue on my UniFi network. So it isn't my specific phone that has an issue. She also doesn't have any issues at her house. It only happens at my place with the UniFi network.

 

*Edit* Another update. When I turn off 5G on both AP's (via WLAN settings), the phone automatically reconnects when I get back in range.

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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

[ Edited ]

I finally fixed it! I did a factory reset on both AP's (holding down reset button for 10 seconds), removed UniFi controller from my Mac and reinstalled everything from scratch. It now works perfectly. When going out of range from the 5G, it first goes back to the 2G. Before the reset it went straight to mobile data (4G). After it's out of range and I get back into range, it gradually goes back from 2G to 5G. Like it's supposed to do. Man Happy

 

So if anyone else has this issue: reinstall everything and hopefully you have the same. Man Happy

 

*EDIT* Well, after half an hour of being happy, I suddenly got disconnected again. Same exact issue. When I get out of range of the 5G, it just disconnects. So it's sadly not fixed. Will fall back to 2G only for now. Any suggestions would be greatly appreciated!

Senior Member
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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

Few things should be happening:

1) AP should send beacons every 0.100ms for every SSID it has configured

2) The client should send Probe Request for the SSIDs it has saved (profiles) when performs active scanning (e.g looking for the wireless networks)

3) If AP "hears" Probe Request either for the SSID it has configured or for the wildcard SSID name it has to reply with a Probe Response message

 

Are you ok getting monitor mode PCAP using your MacBook when the client is attempting to connect:

https://help.ubnt.com/hc/en-us/articles/221029967-UniFi-Troubleshooting-Connectivity-Issues#wireshar...

Thanks,
Myky
CWSP
--------------------------------------------------------------------------------------------------------------------------------------------------
Don`t blame the device as it`s always doing what you have asked it to do, this is not always the same as what you want.
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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

Thanks for your reply. I used Wireshark for three different captures. The MAC address for the phone is dc:f7:56:7c:1c:b0, but I think it shows up as 'Samsung' during the capture.

 

Capture 1:

1) I forgot the network on my Samsung A50 phone before I started the capture.

2) When I started, I joined the network on my Samsung A50 phone.

3) I moved out of range of the 5G and my phone went to mobile data (4G).

4) I came back into range and it didn't automatically reconnect. I clicked on the network to join it again multiple times, but nothing happens.

5) I turned the WiFi on my phone off and on again and it reconnects.

 

Capture 2:

I started the capture after I got disconnected and retried joining the network.

 

Capture 3:

I started the capture right when I started walking out of range. I then went back in to range and tried reconnecting. I also turned off the SONOS device before this capture.

 

I hope this helps. Man Happy

Attachment
New Member
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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

[ Edited ]

Here's also a tcpdump I did from the AP.

Attachment
Senior Member
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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

Hey,

 

PCAPs 1 and 2 don't contain useful info, however, PCAP #3 (5GHz band PCAP) clearly indicated that the phone fails to reply to the initial 4-way handshake packet:

 

5.JPG

 

4-way handshake process can be found in the KB below:

https://wlan1nde.wordpress.com/2014/10/27/4-way-handshake/

Thanks,
Myky
CWSP
--------------------------------------------------------------------------------------------------------------------------------------------------
Don`t blame the device as it`s always doing what you have asked it to do, this is not always the same as what you want.
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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

[ Edited ]

Okay, thanks for looking into it! Any ideas on how I can fix this? Or is this something Samsung or Ubiquiti has to fix via an update or something?

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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

To me, it is a client issue, as the client never responds back to the initial 1/4 message of the 4 - way handshake.

 

Spin 2 test SSIDs on 2.4 and 5GHz bands (e.g 2.4-test and 5-test) and only on one AP. Connect with your MacBook to 2.4, start the monitor mode PCAP. Connect your phone, go out of range, then come back (note the results of the tests). Repeat the steps on 5GHz band. 

Thanks,
Myky
CWSP
--------------------------------------------------------------------------------------------------------------------------------------------------
Don`t blame the device as it`s always doing what you have asked it to do, this is not always the same as what you want.
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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

So I did several tests. All test results are in this ZIP: https://www.dropbox.com/s/9864r0nnp7tilxz/Wireshark.zip?dl=0 (the file was too big to upload here). I hope this gives some information.

 

Downstairs
I first tried testing with only the downstairs AP enabled. I did three tests:
1) Network with only 2.4GHz enabled.
2) Network with only 5GHz enabled.
3) Network with both 2.4GHz and 5GHz enabled.

 

2.4-test-downstairs: Only turned on the AP downstairs with 2.4GHz. Took a long time for me to get out of range. When I got back, it automatically reconnected to the AP.
5-test-downstairs: Only turned on the AP downstairs with 5GHz. Took longer than previous tests to get out of range. The Samsung device automatically reconnected to the WiFi. Did this test three times and all times it reconnected. I recorded two of them.
dual-test-downstairs: Only turned on the AP downstairs with 2.4GHz and 5GHz turned on. Same as the 5GHz tests. It reconnected after coming back into range.


Upstairs
After everything downstairs worked, I started testing the device upstairs. I disabled the device downstairs and did the exact same tests.

 

2.4-test-upstairs: Only turned on the AP upstairs with 2.4GHz. Same results as the downstairs AP test. It reconnected.
5-test-upstairs: Only turned on the AP upstairs with 5GHz. Same results as the downstairs AP test. It reconnected.
dual-test-upstairs: Only turned on the AP upstairs with 2.4GHz and 5GHz turned on. Same results as the downstairs AP test. It reconnected.


Both AP's turned on
Now to test if it works with both AP's turned on. This time I started with both 2.4GHz and 5GHz turned on.

 

dual-test-both: Both AP's with 2.4GHz and 5GHz turned on. The first time it somehow reconnected. Because this is the specific case where it previously failed, I started testing it again. The next two tests failed. It disconnected really fast and wasn't able to reconnect. I started noticing something. The connection only dropped when I was connected to the downstairs AP and went out of range of it, into the range of the upstairs AP (which is in range in our garden). I tested this in the fourth test and it indeed dropped when I started at the downstairs AP and moved to the garden, where the upstairs AP has better range. I tested it a fifth time, starting at the garden, going out of range of the upstairs AP, going back into range of the upstairs AP (it reconnected!), going towards the downstairs AP and then moving to the garden again. When I went to the garden it disconnected and I wasn't able to reconnect again.

2.4-test-both: Both AP's with 2.4GHz. As I expected, this worked without any problems. It disconnected between the two AP's, but reconnected right away.
5-test-both: Both AP's with 5GHz. I expected this to fail the same way as the dual test with both AP's. I started at the downstairs AP and went to the garden again. But it somehow stayed connected. When I went totally out of range and went back, it reconnected. I've tested this several times and it didn't disconnect. And when I went out of range and back in, it reconnected.


So the problem only seems to happen when both AP's are turned on and both 2.4GHz and 5GHz are enabled. And it only happens when I'm connected to the one downstairs and get disconnected from that one. But somehow that's not the case when only the downstairs AP is turned on. Only happens when both of them are turned on. So the captures dual-test-both-2, 3, 4 and 5 are the tests that failed. All of the other ones worked.

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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

[ Edited ]

Hey,

 

I see you enjoyed taking monitor mode PCAPs, well done)) 

My observations:

 

1) The issue happens on 2.4GHz radio (g) when both bands are active. 

 

I see very odd behaviour from the client. When it is out of range it should be completely disconnected from the AP (no wifi wireless symbol). When it is back in range it should start the connection with the  Association Request packet followed by the 4-way handshake (good example from your PCAP below):

 

2_.JPG

 

The phone, however, starts the connection with Reassociation Request. This should only be happening during the roaming between the AP on the same SSID. (bad example below):

 

1_.JPG

 

All dual-test-both-2, 3, 4 and 45 PCAPS show the above behaviour. 

So the client sends Reassociation Request, AP AKCs it but never responds back with Reassociation Response. 

In my opinion, it should not respond and it is expected behaviour because it is expecting to see Association Request for the new session in the first place. It's like the phone thinks that it is still connected to the SSID and it is performing roaming. 

I would raise this with the phone vendor.

 

Hope it all makes sense.

 

Thanks,
Myky
CWSP
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Don`t blame the device as it`s always doing what you have asked it to do, this is not always the same as what you want.
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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

Thanks for looking into the issue! I will get in contact with Samsung to see if they can help me out. I'm also in contact with Ubiquiti, so I hope they can also provide further support. Man Happy

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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

[ Edited ]

Just to let you know.

Same problem here.

To me it looks like the problem started with the last update on the phone.

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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

Good to know there's someone else who also has this issue. I hope Samsung comes out with a new update that fixes this. I couldn't find anyone else having this issue so far, so I hope it's on their agenda. I sent this topic to their technical support, so hopefully they'll respond. I'll also give them a call tomorrow. Man Happy

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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

Share the link with our findings with Samsung support. I found phone’s behaviour unusual.
Thanks,
Myky
CWSP
--------------------------------------------------------------------------------------------------------------------------------------------------
Don`t blame the device as it`s always doing what you have asked it to do, this is not always the same as what you want.
New Member
Posts: 14
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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

Yes, I've shared it with Samsung support. Also opened a thread on their forum:

https://us.community.samsung.com/t5/Other-Mobile-Devices/Samsung-Galaxy-A50-has-problems-with-Ubiqui...

 

Let's hope they can find the problem and fix it in the next update. Thanks for all the help! Man Happy

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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

[ Edited ]

Small update. My sister-in-law also has a Ubiquiti network and was experiencing the exact same problem with her Samsung Galaxy A50. So that's another case where it happens. I got a message from Samsung support that I need to contact the support in my country. Not sure why, since it's a software issue and they don't create the software in my country. But I'll get in touch with my local Samsung technical support.

 

Anyone from the US/Canada who has this issue? Please leave a message in this forum: https://us.community.samsung.com/t5/Other-Mobile-Devices/Samsung-Galaxy-A50-has-problems-with-Ubiqui...

 

*EDIT* I've called the technical support in The Netherlands and they're putting this issue on their agenda. I showed them this topic, so they have some extra information as well. They're working on a new update, so hopefully that one will also fix this issue. Fingers crossed! Man Happy

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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

Keep us posted!

Thanks,
Myky
CWSP
--------------------------------------------------------------------------------------------------------------------------------------------------
Don`t blame the device as it`s always doing what you have asked it to do, this is not always the same as what you want.
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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

Just installed a new Samsung Galaxy A50 update which promised better WiFi stability. I enabled the 5G on my AP's and so far it seems to work. One time it disconnected to 4G, but reconnected again right away. So I hope this fixes the issue. I'll let you know in a couple of days if I've had any problems. I'm also updating my AP's to the newest firmware version (4.0.42.10433), to see if that changes anything.

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Posts: 14
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Re: Samsung Galaxy A50 doesn't automatically reconnect to UniFi AP-AC-PRO

After a few days everything is still working great! So the problem has been fixed for the Samsung Galaxy A50. Simply update it to the newest version. Man Happy

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