I didn't find anything in the sql logs.

The status of the messages where all 'sent' so technet adviced to check the exchange settings.

I found the solution by copying the syntax...

It was the intelligent message filtering rating which was set too low.

This prefented the exchange server of delivering messages without a subject or of messages with a subject and/or...

I found the solution.

Apparantly the length of the @Subject parameter had to be filled out.

This was a configuration on the exchange server.

Thanx.

This can be closed.

Both services have the same startup account.

I restarted both services but problem persists.