I've been trying to access the Discord using the link in the game jam page, but Discord keeps giving me an error that says "Whoops... Unable to accept invite". I'm wondering if the link has expired, is protected, or otherwise just invalid.

The link is working for me. Are you perhaps at the Discord 100 servers limit? If not, try this link: https://discord.gg/ANnA44bWE

I'm nowhere near that limit lol, but your link worked. Not sure why the original one didn't. Thank you!