IP phones getting unregistered multiple time in a day

[technotux]

I have 3CX installed on Debian on Microsoft Hyper-V, version 18.0 update 9, and have around 75 Grandstram 2601P IP phones connected in the network, most of them get unregistered multiple times in a day, and if I restart the phone, it works correctly for some time, during the unregistered state to ensure network connectivity, I have trined pining the phone, accessing the web interface of the phone, pinging the 3CX server from phone diagnostics options, everything works perfectly.

What could be the issue, and why phone are getting unregistered?

 

[Charles_3CX]

How are the phones provisioned? Are they behind 3CX SBCs?

 

[technotux]

Phones are in same LAN subnet and some are in other VLAN routing done on L3 switch… all phones are provisioned using 3cx configuration URL…

 

[TheodorosG_3CX]

Loosing registration actually means that the phones are not able to contact the PBX server.
You need to check on your local network.

 

[technotux]

I can confirm phone are able to ping 3cx server that same time it is in unregistered state, i have checked connectivity from phone diagnostics also there is no latency and i can able to ping phone as well from 3cx server

so there is no network issue

 

[TheodorosG_3CX]

Just checking the ping option will not give enough information.
Have you ensured that sip registrations arrive to the PBX?

 

[technotux]

Just restarting the phone resolves the issue for sometimes, what to check to ensure SIP registration arrives at PBX

 

[TheodorosG_3CX]

Running captures will give you all the information.
Keep in mind that the registrations might also arrive to the PBX but you need also to check whether the PBX replies reach the phones.