Problem with PGP-signed E-Mails

[T. Mohrfeldt (Liesegang GmbH)]

Hello fellow Kolabusers,

I've recently installed the enigmail-plugin for roundcubemail and so far 
it's working fine,

however as soon as I try to send a message signed and not encrypted with 
PGP the signature is valid in my Sent-Folder but invalid at the 
receiving Inbox. I am a little bit puzzled, can DKIM signing be the 
problem? And if so how can I solve this (if it' solvable...). What else 
could be tampering with my sent mail?

I hope this problem is within the scope of this mailing-list, if not, 
sorry from my side.

--
With kind regards

Torben