Invalid “To” e-mail address – (followed by array of 3 email address)

I have a ninja form plugin that won’t email the submissions of forms. All other emails work (orders, success emails, new user registration) but it just won’t send this one forms submission email. This is the error it shows. Email could not be sent. Error: Invalid “To” e-mail address “a:3:{i:0;s:15:”[email protected]”;i:1;s:21:”[email protected]”;i:2;s:20:”[email protected]”;}”