Instantly fail to connect to server when running modpacks

I am trying to connect to the server on 1.21.1. I am able to connect just fine through my forge client without any mods installed but as soon as I try to join with any mod, it instantly fails to connect. These are completely client side mods, stuff like better 3rd person or sodium. I have tried both forge and fabric, on multiple versions, and each time I have a single mod it immediately disconnects. I have also tried both the Wynnic Enchantments modpack and Wynncraft for Lunar Client, and despite them being made specifically for the server, I get the same exact result. I haven't found any discussion of this specific issue online, does anyone have a clue what is going on? I'm sort of at a loss.


The specific message I get is:

Failed to connect to server
Disconnected