Email marketing, sending draft fails

Hi, Kentico 11 ultimate edition - Email marketing application

When i try to send a draft email i get an entry in my eventlog saying "Message: Invalid URI: The format of the URI could not be determined." with source of "DraftSender+<>c__DisplayClass5_0" This only happens on my production environment.

I have a local installation running on my laptop under IIS under a somesite.localhost. This does not have the issue.

Also on my produciton server I have an issue with the preview function of the newsletter. This also complains about "Message: Invalid URI: The format of the URI could not be determined." Apart from this I have not noticed any other differences between the local version and the production version.

Could I be so lucky that someone could point me in any direction or experienced this before?

Cheers Magnus