As the message says, a portal room already exists for that chat and you don't have permission to unbridge it. You'll probably need the bridge admin to help.

[mopo3of]

          As the message says, a portal room already exists for that chat and you don't have permission to unbridge it. You'll probably need the bridge admin to help.

GitHub issues are for bridge bugs and feature requests. For issues with configuring self-hosted bridges, ask in the Matrix room linked in the readme. For issues with bridges that you aren't hosting yourself, contact the bridge admin.

Originally posted by @tulir in #900 (comment)

[mopo3of]

I'm the administrator, I created a chat in tg in a minute before, so it couldn't be joined into any other rooms, I can read.

[3ynm]

I've tried joining a supergroup using t2bot.io utwente.io and tchncs.de

I always receive the same message.

I can bridge to a regular group and then convert it to supergroup, the bridge does not die. But I can never join a group with IDs starting on -100.

@tulir Maybe you could check if this happens to you?

[ValRahl]

In a Telegram supergroup with Matrix bot you can try /invite to join. Type in the chat of the Telegram group, /invite and your Matrix ID ("/invite @example.element:matrix.org). Worked for me in similar situations.