What is expected behavior with 3PIP phones (registered to SFB Server 2015) with a Teams meeting?
When I say that if the phone is registered to SFB O _ it will happily join a teams meeting (from the calendar meeting invite)
When the phone is register to SFB Server _ it fails (from the same calendar meeting invite)
In the SIP trace I see the following error on the SFB Server _ "Start-Line: SIP/2.0 413 Request entity too large"
ie the phone on clicking _ "Join" button sends an invite to the SFB Server
The server responds with the 413

The project intent was to move to "SFB with Teams Collaboration and Meetings".
Keeping telephony on SFB server but using Teams for meetings etc. However this issue is a bit "awkward" if the phones can't join meetings