Yesterday eve Exchange just started not to work fine. Exactly the SMTP Virtual Server stopped and was unable to restart, no matter what i tried to do. Long story short: at last i decided to remove SMTP from Windows Component \ Application Server \ IIS \ SMTP Service and then reinstall it again.
That fixed the problem whit SMTP Virtual Server - it works now like a charm BUT emails sent from one user to another are not delivered. Moreover they 'disappear' as the senders has no error message it seems mail is sent but the recipient never gets it.
(have no idea about emails from / to mail-addresses outside of AD as InternetService is during rebuild at the moment which means we have no internet at all in the next 15-20hours)
Event log shows this:
A non-delivery report (reason code unable-to-transfer and diagnostic code unrecognised-OR-name) is being generated for message C=US;A= ;P=First Organizati;L=DC1-080521113704Z-10. It was originally destined for DN:CN=KOVACS.PISTI,CN=RECIPIENTS,OU=FIRST ADMINISTRATIVE GROUP,O=FIRST ORGANIZATION§ (recipient number 1), and was to be redirected to . [MTA DISP:RESULT 16 136] (12)
Im quiet sure its a simple problem im just dummy to find it out what :)