Symantec Mail Security 5.0.1 for SMTP run one year without problems. After time it stops arrive new e-mails with following errors:
Event ID: 4006 Source: smtpsvc Description: Message delivery to the host '127.0.0.1' failed while delivering to the remote domain 'domain.fqdn' for the following reason: The connection was dropped by the remote host.
Event ID: 7031 Source: service control manager Description: The SMS Filter Hub service terminated unexpectedly. It has done this 1 time(s). The following corrective action will be taken in 0 milliseconds: Run the configured recovery program.
Solution is described on Support page of Symantec. Just apply “Symantec Mail Security 5.0.1 for SMTP Patch 200”