Reconnect loop on Android 16.7.5.103

[yetopen]

Hi.
3CX 16.0.5.619, Android 16.7.5.103. Since last Friday, with no change on the network or on the installed system, the 3CX Android app stopped being usable. We cannot tell what happened since then, but as of today the app connects, the indicator remains green for 5-7 seconds, then the status shows Reconnecting. Within 1s the status is back to green and so on forever. This makes calling impossible, as the conversation is disconnected around every ten seconds.

Physical phones (Fanvil) in local LAN have no problems.

What could cause this behaviour?

Thanks

 

[ChrisC_3CX]

First thing I'd recommend is upgrading the 3CX PBX to the latest stable version which is v16.0.8.9. If the issue persists after doing so, please go ahead and provide the relevant information mentioned here: https://www.3cx.com/community/threads/every-new-post-must-contain.20492/

EDIT: Also, make absolutely sure that UDP port 5090 is forwarded to the 3CX PBX.

 

[yetopen]

I've upgraded to 16.0.8.9 and it's still happening
Ran the firewall test everything is green.

While compiling the info below I made a test using 3G connection and it doesn't happen, it works well! I was able to make a conversation for minutes. While reactivating wifi triggers the disconnections...

Other requested information:

• Phone Model: Samsung S10e (but happening with several other Android devices)
• Android Version: Android 11
• App Version: 16.7.5.103
• 3CX PBX Version: 16.0.8.9 on Debian9
• Network Connection: WiFi IPv4
• Client is on the same network as the PBX or not? No, all tests were made via internet

 

[Vali_3CX]

Thanks for feedback!
You said on 3G is working OK, only on WiFi this issue occurs. On ANY WiFi? I mean, let's say, on both the one at work and the one at home?

 

[yetopen]

Thanks for feedback!
You said on 3G is working OK, only on WiFi this issue occurs. On ANY WiFi? I mean, let's say, on both the one at work and the one at home?

Yes, it happens in several different wifis on different phones

 

[oleg.seagull]

Having the same issue.Exept we're on 16.0.9 PBX version. And it's happening via mobile internet also as via external WiFi. The same is true for iPhone devices also.
It started after last app update at friday.
5090 UDP and TCP ports are forwarded.

Everything works fine in the internal office network.

 

[Vali_3CX]

Android update available
https://www.3cx.com/community/threads/update-android-client-reconnection-issue.81854/

 

[yetopen]

Android update available
https://www.3cx.com/community/threads/update-android-client-reconnection-issue.81854/

Thank you, indeed this fixes!!

About

However, for PBX admins, I would highly recommend to figure out, in the first place, why the tunnel UDP port is not available; not having the UDP channel available definitely have a negative impact on audio delay and reconnection speed of the clients.

Is it 5090/UDP?

 

[ChrisC_3CX]

Is it 5090/UDP?

That is correct, it is the Tunnel UDP port which by default is 5090. If you changed it then it is the udp port of whatever port number you set it to be. You can confirm this by taking a look in "Management Console >> Settings >> Network >> Ports >> Tunnel Port"

 

[yetopen]

That is correct, it is the Tunnel UDP port which by default is 5090. If you changed it then it is the udp port of whatever port number you set it to be. You can confirm this by taking a look in "Management Console >> Settings >> Network >> Ports >> Tunnel Port"

I confirm it's 5090, and that bot TCP and UDP protocols are forwarded to the PBX

 

[ChrisC_3CX]

I confirm it's 5090, and that bot TCP and UDP protocols are forwarded to the PBX

Excellent, in that case, if the issue persists, you might want to investigate further by monitoring this traffic on the firewall in order to determine if any packets for port 5090 are being discarded for any reason.

 

[yetopen]

Excellent, in that case, if the issue persists, you might want to investigate further by monitoring this traffic on the firewall in order to determine if any packets for port 5090 are being discarded for any reason.

With the app update it works fine. To debug I'd have to disable the TCP port on the firewall and then dump the traffic? Unfortunately it's a busy customer and I cannot make any further test on this install, I wonder if @oleg.seagull is able to do them

 

[ChrisC_3CX]

With the app update it works fine. To debug I'd have to disable the TCP port on the firewall and then dump the traffic?

TCP port 5090 is actually required too so both UDP and TCP port 5090 should be available.

 

[oleg.seagull]

Hi. A little update FYI
I was able to solve the problem without installing updated app.
Previosly our firewall rule allows only recieve UDP 5090 port traffic. Since i allowed recieve AND send traffic for this rule the connection become stable again.

I just want to mention that everything worked fine with the "receive only" setup till 16.7.5.103 update

 

[ChrisC_3CX]

@oleg.seagull
Great news! Thanks for sharing!