Microsoft making some changes to Teams Direct Routing
On March 1, 2022, Microsoft will be removing support for sip-all.pstnhub.microsoft.com and sip-all.pstnhub.gov.teams.microsoft.us FQDNs from Direct Routing configuration.
Note: If you aren't using Session Border Controllers you can safely disregard this message.
How this will affect your organization:
When this change is implemented, if no actions taken and sip-all FQDN is used, users will no longer be able to make or receive calls via Direct Routing.
What you need to do to prepare:
Customers will need to use the recommended subnets (18.104.22.168/14 and 22.214.171.124/14) for any classification or ACL rules and discontinue using the sip-all FQDN when configuring Session Border Controls for the Direct Routing.
Source: Microsoft MC307310