I searched all over your forums and tried everything I could in terms of setting up my DomainKey for my domain (dinaandeugene.com). Quotes, no quotes, semicolons, etc.
My host (knownhost) assures me that everything on their end is functioning perfectly, and that the problem is on the CM side. They said:
The WHM generated domainkey is working, so its not a server side issue. It seems to be an issue with 'Campaign Monitor' generated key.
Its better to contact their support to seek assistance. If anything need to be changed in the server to make it working, we can change it for you.
What can I do?
I have the same problem. A previous thread found via Google did not appear to have (confirmed) definitive answer:
Since cPanel/WHM is a popular server admin software, I would have thought that CM would provide some help info for this specific issue.
If you get in touch with support we can take a look at your specific domain and the visible DNS for it and see if we can spot the issue.
Unfortunately, we're not able to provide specific instructions for every panel configuration, even cPanel has numerous versions in use out there and variations on a per host basis.