Email Unsubscribe is failing

Folks,I am decluttering my primary email account....Received a marketing email from Ring. Followed the unsubscribe link....Logged in with my standard, primary email address.Went to email preferences, selected unsubscribe all correspondence.Website says "Invalid email address." Mind you... the site AUTO-FILLED the unsubscribe email address from my profile. I tried to game it.... all lower case... add a hard space after .com... all to no avail. Your verification code is broken. Please go backdoor and unsubscribe me. HAPPY to resubscribe to a passive email account where I don't mind accumulating marketing noise.Please confirm when unsubscribe is completed. Thank you!Dave Donhoff