Don’t want to sound like I’m victim blaming the author. But I can tell you exactly the issue with their account: registering with an email on a self hosted .xyz domain. Using sketchy tld’s is just asking for this kind of trouble.
They had one of the cheapest registration costs. And so ended up with a high concentration of spammers compared to older established tld’s like dot com. Using the tld for legitimate purposes is really challenging due to the high number of systems that flat out blacklist it.
xyz has been accomodating to scammers ever since its inception. After a decade I think we can say that it is on purpose.