We cannot figure out why. Contacting CM by email results in very complicated instructions for "Domain Keys" on servers we have no control over and don't understand the technology anyway. That's why we pay to use Campaign Monitor - so we can just design and send and not have to worry about servers and the underlying technology.
It is getting frustrating and our clients are threatening to stop using us. The head of the company says all emails from us go straight to his junk mail folder!
Is there anything in our email itself that would trigger this? Please look here:
Having links that just say 'click here' may not help.
Some of it may depend on the subject line that you use.
And although you may have no control over the servers, just ask to be put in touch with their IT send them the instructions... you don't have to get involved other than saying this is a really important way of verifying that the email is authentic.