Totally. I recently set up email on a few domains, backed by protonmail. Most of them work just fine. But my internationalized domain -- a .com in fact -- can't send email to Gmail, it is wholly rejected (I get a bounce-back failure notice, and the email never gets to even the recipient's spam folder).

There doesn't seem to be any way to tell Gmail that this email is fine, in fact it's coming from me.

Meanwhile countless horrific obvious spam gets through to my gmail just fine, much of it straight to my Inbox.