Any ideas what could be causing this?
#Wall of text appears when attempting to join into a multiplayer server
dreamy pasture
subtle meadow
You most likely have a mod on your client that isn't on the server, or vice versa. I'd triple-check that there are no differences between what you have in your instance, and the mods the server requires.
If you need help trying to spot different mods, the log may have that information, but to make it easier for others to help you I recommend uploading the log to https://mclo.gs/ and sharing the link so anyone can view the full log!