This problem occurs if the sharing policy doesn't allow the user to share the level of detail that the user set in the sharing invitation.   Connect to Exchange Online by using Remote PowerShell.

Determine the sharing policy that's assigned to the user. Run the following command and note the policy returned.  Get-Mailbox User1 | fl...

If you receive this message while attempting to login to a Windows machine locally or while using RDP (Remote Desktop), ensure the Netlogon service is started on the host.   Go to Start menu and type services.msc then enter key.

Search for Netlogon and ensure it is set to automatically start and then start the service. If the service...

Did you receive a prompt while working in Microsoft Outlook? The message reads This is not a valid number. In most cases, you were typing a message in Outlook and the dialog box appeared. You click OK and the box disappears. There is no known knowledge base article on Microsoft’s website for this error message, however...

Did you receive an odd message from Battle.net while attempting to play StarCraft online?   You have either been playing too long or you are not permitted to play at this time of day. (Failed to make initial server connection (Error 2:64))

  This happened to us after launching Battle.net, logging in, and attempting to...

If you attempt to remote desktop (RDP) or connect to a Windows server, you may receive a message about the server not responding.   The server isn’t responding We’ll wait a little longer for the server to respond before automatically reconnecting.   The remote terminal server is likely too busy to accept new connections. This includes...