OnePhoenix

Is there a logistical/technological reason why I can register for a protonmail account on my desktop without issue but when I try on mobile it tells me "there has been suspicious attempts from your server and we have stopped sending new codes"?

GrapheneOS on mobile MacOS on desktop Both running through protonVPN

I used to use Protonmail, however the verification steps become tedious when creating unique emails for sign ups. I've switched to Tutanota despite it contravening their one account policy. What do you all use for one off emails (for sign ups etc )? Or do you prefer one of those 10 minute email sites?