Call queue-Transferring calls to a Sfb user not working

[Adrian Mataisz]

Transferring calls to a Sfb user, when received from a call queue for hybrid users (PSTN on prem), is not working since this week. Anyone experiencing this behavior?

 "The call couldn't be transferred.    Call was no transferred because there was a problem with the calling service"

Calling directly  SIP user- transferring works.

I'm am fully online with PSTN  and DID from MS and transferring from the call queue is working for me, this behavior is only for users who have DID and PSTN on prem. 

I opened a ticket with MS

[#2]

The age of question, what has changed in your environment?

A potential cause could be IP and URL changes https://docs.microsoft.com/en-us/office365/enterprise/urls-and-ip-address-ranges since your issue started last week, this post was update around the same time.

[#3]

Thank you Andrew. I'll check with our network team.