It is always best practice to ensure that you have the latest version of the Exchange connector on your Exchange Server.
Exchange Connector - Exchange Connector (Current version is 2.2.3) Transport Agent - Exchange 2013 or above (Xink_Agent.msi), for Exchange 2010 (emailsignature_exchange (v2.0.1).msi)
Note: Exchange connector version 2.1.0 requires .NET 4.7.2 runtime or higher (Download .Net Framework)
