Identified - Microsoft have acknowledged an issue with Teams whereby the following functionality may be unavailable:

Create Teams Channels or Threads,
Create or join Teams calls,
Update Team names or descriptions,
Place outbound Public Switched Telephone Network (PSTN) calls.

The incident may be followed by accessing the Office 365 portal: https://status.office365.com/

VIA provided infrastructure is performing as expected and healthy. If you wish to seek further information regarding this incident, please speak to your Office 365 Support Representative.
Jul 11, 13:21 BST