Outgoing calls from teams dropped

[Dan____]

All outgoing calls are being dropped after about 10 seconds of silence with Q.850 ;cause=22 being returned to the SBC and the following error displayed to the user:

It only happens in one of our offices if the same account logs into a machine in a different office it's fine and it never occurs on the WebClient only the desktop client.

Anyone seen this before?  

[#2 · Accepted solution]

In case anyone comes across this post in future, it turned out to be a firewall issue whereby one of the MSFT servers was blocked, but this did not affect the regular Teams usage at all only PSTN it also didn't effect the Teams web client

[#3]

Hey @Dan____ having the same issue on our side but on handsets. What were the MSFT servers that were blocked?

Thanks

[#4]

@Henry MoralesUnfortunately I don't remember our exact case but I think it was to do with sip.pstnhub.microsoft.com there is a docs page on the SIP signaling fqdns that can be found here that might help.

Hope that is able to point you in the right direction.

[#5]

@dan_ ___

But what if user is connected to the home network. Does firewall play any role between it ? 

I dont think so. Could you please suggest what we can do further to isolate this ?

[#6]

This really depends on how the end users machine is configured.

If it is just a standard home PC connecting to a home internet connection then I would not expect this to be an issue.

If the user is on a corporate laptop it could be configured to use a VPN or proxy etc. 

[#7]

Hello @dan,

Thanks for the response. Yes this is the corporate Laptop. But it nit contain or user VPN or Proxy.
It is just using ZSCALER . Which even we tried bypass & disabled but unfortunately the situation is same for us. It doent matter whether they are in office or Home network. Issue remains same with the one location & with the certain Laptops. May we know where you have enabled or what ?