We have set up a public group (nip-29). If you’d like to report a bug or ask any questions, you’re welcome to join.
Simply enter the group link below in the search box on the Keychat browser page, or search for “Keychat” in Chachi:
Discussion
It fails every time I try to join. I'm successfully logged in and able to chat with other groups, but not Keychat.
This is a bit odd. I just successfully joined using a different npub, and I haven’t changed any of the default settings since creating the group. I’m not sure what’s causing the issue.
"Failed to send join request"
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.
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.
seems keychat doesn't support Amber...?