Actually, the problem happens whenever I load a group I need to join to chat. If I go to a group that doesn't require Join, I'm able to chat. So it's something with the Join function that I'm having trouble with.
Discussion
Try logging out and then logging back in. I’m not sure if that will resolve the issue. 
No good. Same problem. I'll tinker with it and see if I can jam a few parts together and make it work 😉
I went to my FF browser and went to the chachi URL you provided, logged in with my browser extension (Nos2x), and was able to successfully join the Keychat group. So whatever the issue is is related to the Keychat integrated browser.