When trying to enter Minecraft Realms with an Add-ons it loads infinitely, in 1.21.1 sometimes the Add-on would not load, but restarting the realms sometimes worked (probably it is associated with this error).

Currently, if I try to enter the kingdom with a world with an add-on included I get this , but if I enter a world without the add-on it loads perfectly
Note: When the update came out, and we updated the world to 1.21.2, we were able to log in to play, but the second time we tried to log in it gave us the error.