Hey, I solved the problem. Even though Mercury only allows relaying if you have the right credentials, it works if I leave user and pass blank. If I put in the right data, i get the error: smtp authentication failed. Gosh, these computers just drive me mad.
To enable debugging output, set $Self->{Debug} to something higher than 1. You may enable debugging ouput in your Config.pm or just restrict it to a single module by editing the sources directly. Take care when doing so.
Use this command to find all possible locations to set the Debug value: egrep -nr '\$Self->{Debug} = .;' /opt/otrs You will find a comment explaining the different debug values possible, but you may safely use value 9 to always spit out the maximum info available.
I enabled Debug in my Config.pm file, but it still get the same output. Strange. Have a nice day, Andi Bublitz