I apologize you received this error message! With that said, I have taken a look at your account and can see you were able to schedule your most recent campaign. Are you still in need of assistance? If so, it's important to point out we have usually seen this happen with a subject line that contains &N; (ampersand, any letter, and a semicolon). The workaround we suggest is to remove any instances of a & character, letter, semicolon from the subject line and reword it to not have those characters in that order. You can have an ampersand, letters with spaces, and a semicolon (Ex: &the word;), but if there is no space between any of it (E: &theword;) then you will continue to receive this error.