Error 554 with response code 250

Your software
My Mautic version is:
My PHP version is: 7.1

My problem is:
(Expected response code 250 but got code “554”, with message "554 Message rejected: Email address is not verified.)

The email is being sent from the contact and saying it is not verified.

I am sending the contact an email. There would be no way for me to verify the contact email address.