Solved Inbound calls only to 3CX but not to Teams, Outbound ok

[dsanetops]

Hello, our 3CX sits in the middle of Teams and another IPBX,
Calls from Teams bridge successfully to the outside world (IPBX internal users and PSTN line)
However the in the reverse direction, calls come to 3CX and ring on a phone or web client registered on 3CX but not on the corresponding Teams extension.
The extension is correctly assigned to the user and I can see it in the dialer.
Any pointers?
Should the called party be the full E.164 number in teams or is it ok to just route to the extension?

 

[NickD_3CX]

Hi!

If you go to the 3CX Management Console --> Users, next to the users that don't ring on the Teams client, do you see "MS 365+Teams" in the "Synced with" column?


Generally though, have you followed this guide?
https://www.3cx.com/docs/microsoft-teams-business-voice/

And to better understand the setup you have, 3CX uses this "other PBX" as a SIP Trunk to make and receive in/out calls from, right?

 

[dsanetops]

Yes, I can see user is synced as MS 365+Teams.
And you are right, the other PBX is just a Cisco Callmanager cluster to which the PSTN is connected.
I have followed the guide you shared in order to build the integration.

 

[NickD_3CX]

If you log into the Teams Admin portal and go to Voice --> Direct Routing, do you see any warnings?

It should look something like this:

 

[dsanetops]

Hello Nick.
This is what is see on mine.

 

[dsanetops]

Call to T:Extn:1001@[Dev:sip:+230xxxxxxx;ext=[email protected]] from L:3.1[Extn:1003] failed, cause: Cause: 503 Transport failure: no transports left to try/INVITE from local

Hello Nick.
Each time I am trying a call, I can see the following logs.

 

[NickD_3CX]

Your problem might be related to the Warning in the SIP Options column you see.

Can you please send me the Teams FQDN and your 3CX FQDN in a PM so I can check?
Also what certificate did you use? Was it a wildcard certificate?

 

[dsanetops]

Hello Nick.
Info sent via PM. No I don't use wildcard. I have a fqdn specific certificate for this.

 

[dsanetops]

It's working now.
I did a few changes, and not sure which one got it to work.
1) changed the direct sip calls domain from sbc.domain.com to domain.com
2) the port that it was listening on previously was 5061, but after doing the above change, it moved to 5062.
I re-aligned SBC port to 5062 in teams again.
3) I saw that 5062 was not open on firewall and I had it opened.
I waited and this morning it seemed fine.
Now I can call back and forth between Teams and CUCM and external

 

[NickD_3CX]

Good to hear it is up and running now!

I'll go ahead and mar this thread as 'Solved'.