Hi,
We had the same issue as well and managed to resolve as follows
- In the metabase file below the first (i.e. /LM/SmtpSvc/1/) IIsSmtpServer node there are several other nodes such as IIsSmtpAlias, IIsSmtpDl etc.
- Copy all of them and replace the /LM/SmtpSvc/1/ with /LM/SmtpSvc/2/ and paste it under the second IIsSmtpServer node.
- Now restart The SMTP Server and it should work.
Hope it helps someone.