Guildfinder seems to be broken for several realms after the connections. Guilds get delisted after a few days without any sign except searching for them in the guildfinder. You have to unlist and relist them to get them back up, and much, MUCH worse, applications to guilds aren’t going through. On the applicant side they list as pending and look normal, but on the guild side there’s nothing. Shows as if there are 0 applicants.
If you recently merged with a realm and tried to join a guild with no answer, it’s possible they just didn’t see it.