3cx sometimes not work

[Tomas Raska]

Hello,
sometimes we have problem, that all outgoing calls are not possible. And first after server restart is everything fine.
Can me somebody explain, where I can error find?
SIP Trunk refresh registration not help, only help whole server restart.
Screenshot in attachment.

 

[AWS2P]

hi
when this occurs, do you have always sip channels available? this is not a saturation on your trunk?
trunk is green or red when this occurs ?

where's your PBX, local, cloud?
Is your trunk sip provider a 3cx supported one?

 

[Tomas Raska]

Yes, SIP channels were all available, I think we have 8 channels. It happends after night, when first people want make outgoing call.
And Trunk was green.
We have local PBX on Windows Server 2016.
Deutsche Telekom in Germany is supported SIP provider - biggest operator in country

 

[AWS2P]

Server is dedicated to 3CX ? is your 3CX up to date ? At night is there backups or others tasks on server who may affect PBX?

As you said this is outgoing calls not working, is it the same with incoming calls?

was it working fine previously and now no more? or it has never worked ?

 

[Tomas Raska]

Yes, server is dedicated to 3cx, only this service work on this server.
Server is virtual (esx), backup is done by copying virtual disks when a virtual machine snapshot is created (Veeam Backup).
Only outgoing calls are affected. Incomming calls are OK.
Till today everything was fine (circa 14 days). We had the same problem 14 days ago.
We have latest 3cx v15.5 (becouse we have some CFD, we are still on 15.5)

 

[JohnS_3CX]

Hi Tomas,

Have you tried running the firewall checker to see if everything passes and that no SIP ALG is detected?

 

[Tomas Raska]

Hi, SIP ALG is OK.
I have not from today, but from 14 days ago dump.pcap file for Wireshark with this Problem. Can me help somebody analyze this problem, if is it in this file?

Thanks

 

[JohnS_3CX]

Please do not post the pcap file on the forum because it will contain sensitive information about your system.

The reason I asked about the firewall checker passing is because you described a situation where after rebooting, the trunk will work successfully. The firewall might close down unused ports in some cases so I think you should share some more information like what firewall do you use, and how did you setup the NAT, if you use single or dual NIC (see here please https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/ )

An interesting test you can do, when you come in the office in the morning and the trunk stopped working, just run the firewall checker at that moment to see what result you get before you restart the PBX. This should give us an idea if anything changed unexpectedly

 

[Tomas Raska]

Ok, I'll wait a few days for the problem to reappear, and then inform you with the result - Firewall checker