Can switching from .com TLD to non .com TLD affect emails even if MX records migrated correctly

I have a high-level question about a customer that switched from a .com TLD to a .fun TLD. They didn’t switch hosting, only their TLD. They’re now having issues with their emails, personal and campaign based, being blocked.

Before I dig in to the technical stuff, I wanted to know if anyone had a similar issue. Before I dig in to MX records and such, I didn’t know if there were known TLD issues with ones like .fun, etc. Sorry if this is a vague question. And I promise I’ve been googling and asking first!