Guild Wars 2

if you were trying to join a dungeon/fotm, then your issue is likely the one discussed here: https://forum-en.gw2archive.eu/forum/support/tech/Code-19-9-18-1616-101/page/4#post3200617

if so this has worked for me:

guest to one of your servers (if you’re like me then your guested servers have been decided for you) then leave the area you tried to enter (plains of ascalon for example if you were trying to get into ac) then return to your normal server and you should be fine. slightly ridiculous, but it’s the only way that i’ve found that works; aside from waiting it out i mean

for those who are having issues after not getting into an instance, namely that you cannot select the character at all, one workaround is to guest to one of your servers (if you’re like me then your guested servers have been decided for you) then leave the area you tried to enter (plains of ascalon for example if you were trying to get into ac) then return to your normal server and you should be fine. slightly ridiculous, but it’s the only way that i’ve found that works; aside from waiting it out i mean