Calls from Skype for Business to Teams fail
I recently had a customer who was mid migration from Skype for Business Server On-Premise to Microsoft Teams. During the initial testing phase we got confirmation from users that all features were working just fine.... first mistake, always check all features and functions yourself!! My mistake. What was reported to be happening here was a call would come in to the Skype for Business user on reception, they would search for the Teams user, it would only show "Presence Unknown" and not allow the call to be transfered. In actual fact, the issue was more straight forward than this, they were not able to even call the Teams user from SFB. There were a few things to check here: First, ensure SharedSipAddressSpace is set to True in Office 365. Get-CsTenantFederationConfiguration Identity : Global AllowedDomains : AllowAllKnownDomains BlockedDomains : {} AllowFederatedUsers : True A