no longer have email address and cant validate

I used to have the email shortcut with protonmail ekb155@pm.me When I try to login to move my shortcuts to Linux, it no longer lets me login without validation to that email. The suffix... pm.me is shortcut for protonmail. When I downgraded i kept my main login, kbarnsda@protonmail.com My current address is kbarnsda@gmail.com Is it possible to free up this snag, I have always used Mozilla since the beginning of time. I dont want to switch t o Brave which did allow me to change emails. Any suggestions please Thanks said more simply.. can you change ekb155@pm.me to my new email kbarnsda@gmail.com please for your security chaps the old email ekb stood for everett kenneth barnsdale and pm.me was shortcut email for protonmail.com