My NYTimes sub goes to my gmail, and then it forwards to my fastmail (I rarely need to check my gmail). I was unable to sign up for an Etsy account with Fastma

My NYTimes sub goes to my gmail, and then it forwards to my fastmail (I rarely need to check my gmail). I was unable to sign up for an Etsy account with Fastmail. They only acknowledge the majors. But I was able to sign up with gmail and then promptly change it to fastmail. Really sophisticated opsec on their part.