An error kept me(1.15.2 client) from joining an 1.14.4 server.It occurred after my resourcepacks being changed, idk if this is the reason, so I attach the resourcepacks to this post.

Cerulean-Extension-0.0.3beta.zip
[15-16]DiamondWar0608.zip

It seems you had a hard crash at some point for some reason, or maybe your internet cut out while connecting. You can fix this error by deleting multiconnect's translation cache. Delete the directory at .minecraft/config/multiconnect/caches.

Thanks!