Some clients have problems with the server textures in Dol Amroth. You could try to disable server textures. To do that choose the MCME server in your Multiplayer server list and click "edit server". Then set server textures to disabled.
Join the server with only default minecraft resource pack. Dol Amroth will look horrible

Another thing you can try to fix is deleting the cached server textures on your client. They might be corrupt. To do that go into the .minecraft/server-resource-packs folder and delete all files in there (they have cryptic names like 06d1b4d1fc5941c975b410284d34129b1bac7615). This will cause your client to download them again.