Can not include CC's in E-mail link to pre-filled Email

I am attempting to create a link to an e-mail that would prefill to multiple e-mail addresses and include a subject line as well as the body of the email. When I follow the instructions for the HTML inclusion of CC's to add the additional addresses (or use a generator that includes cc's) the Constant Contact line for address gives me an error message to enter a valid e-mail address. I even cut and pasted a link from an old Constant Contact campaign that worked in the old campaign but will not be accepted in the address line when I attempt to edit the e-mail link in the newly created campaign e-mail link.