After upgrading to or installing Symantec Mail Security for Microsoft Exchange (SMSMSE) 7.5.6, items released from quarantine by email no longer arrive in the intended recipient mailbox, and reappear in the quarantine view. The Quarantine ID number is unchanged on the original item.
In the path <Installdrive>:\Program Files (x86)\Symantec\SMSMSE\<version>\Server\, there is no file called "Symantec.MailSecurity.EWS.Client.tlb".
SMSMSE 7.5.6 and later use an EWS based SMTP client. If the EWS binary is not registered, SMSMSE 7.5.6 will not be able to create SMTP sessions to send notifications or release quarantined items via email.
You must register the Symantec.MailSecurity.EWS.Client.dll.
To register the Symantec.MailSecurity.EWS.Client.dll:
Navigate to C:WindowsSystem32, right click cmd.exe, and select Run as administrator
Run the command cd C:\Windows\Microsoft.NET\Framework64\v2.0.50727
Register the EWS assembly with the 64 bit version of .Net by typing: