I think the registrar makes the difference: autistici.org was registered via Gandi, but noblogs.org registrar is Tucows Domains Inc., which points[1] to njal.la

I think the registrar makes the difference: autistici.org was registered via Gandi, but noblogs.org registrar is Tucows Domains Inc., which points[1] to njal.la, an "offshore" domain hoster that should be more resilient, but isn’t really usable for email hosting, since domains at such a hoster will land on blacklists almost immediately. [1]: https://tucowsdomains.com/provider-result/ https://tucowsdomains.com/provider-result/