Issue: when you attempt to perform a management action you receive the following error message "Data returned by the remote Get-FormatData command is not in the expected format" .
The issue is related to an important issue on Microsoft side on Exchange PowerShell connection. You can refer to the link below for more details: https://answers.microsoft.com/en-us/msoffice/forum/all/cannot-connect-to-exchange-online-via-powershell/25ca1cc2-e23a-470e-9c73-e6c56c4fbb46?page=7
There is no official solution provided by Microsoft but they are committed to understand and resolve the issue.