https://lists.sr.ht/~sircmpwn/sr.ht-discuss/%3C6fe2f6d8-c613-df86-7108-704e34853679%40posteo.net%3E
A user ~phi1_h created a SourceHut Site which does not load on some devices. It's possible it's due to the underscore, which is not allowed in DNS.
SourceHut should warn or reject if a username is invalid in DNS.
A warn seems fine to me, as they may never want to use SourceHut Pages, and if they do they could change their username (#118)