I created the token in the CM transactional page, and am getting the error
" {"exception":"[object] (Swift_TransportException(code: 550): Expected response code 250 but got code \"550\", with message \"550 5.7.22 no valid dkim found
\" at /Sites/dashboard/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php:419)
The error suggests that no valid DKIM record was found.
This is a DNS record that aids in verifying emails sent under your name actually were sent by you.
It is not a Laravel error.
You may want to check that you have completed all your 'setup' steps with Campaign Monitor - most email transactional services require this as part of the 'getting started' process to ensure your emails that you send don't end up in spam.