If you are importing emails into the Message Centre from a Microsoft365/Office365 mailbox, Microsoft require you to authenticate the connection through their Azure portal.

The 'Client Secret' value expires and needs to be updated. When it has expired you will see a Microsoft error message and the following information will appear at the bottom of it:

Information on the creation and updating of the App ID and Client Secret values in the Azure portal are available from: https://incisivesupport.com/docs/Microsoft365_OAuth2_Config.pdf 

In the Incisive application you need to update the Client Secret value in the 'Secret' field in Setup > Provider > Config 3 > Edit, for each Provider.  The App ID does not need to be changed.