A contact's presence status is unknown in MSTeams

    Recently one of our newly joined user had issue that presence status is unknown in Teams. He gets "Unknown status" in MSTeams. He also cannot see the status of others, however all the other applications that use the Microsoft 365 account work properly.

    He was not able to access the status for MSTeams through web, desktop app, mobile and all other ways. Found some articles,  for recommendations to fix this by apply coexsistance change Teams, however, coexsistance change might force reoccurrence meetings to be resend.

   The issue might be related to license assigned to MSTeams, so removed the license for the user from on-prem AD and waited to sync with AAD, once it synced again issued license to the user. 

Note: Through conditional access, we are assigning license for particular security group users, so removed him from that security group and again added.

    We waited for some time till re-assigned license to be take affect. The license is reissued to the user the MSTeams started to work properly.

Note: This may affect the functionality of user's other services like Email and all, so plan accordingly.

Problem with attaching files in Teams chat or channel

 Error:

 When user is trying to upload files using MS Teams for a channel, getting files are locked error.

Cause :

The user does not have corresponding MSTeams channel site access.

Note: Every MS Teams channel has its own SharePoint sites. So when we upload files in MS Teams it will upload in SharePoint. So the affected users can verify themselves whether they have correct permission to access the MSTeams channel site access , click POSTS tab then  three dots (...) --> Open in SharePoint option. 

Solution:

Check respective MSTeams channel's SharePoint site permission for the user and assign required permission for the user.