That Telegram chat has no existing portal. To confirm bridging the chat to this room, use !tg continue

Bridging complete. Portal synchronization should begin momentarily.

In reply to @telegram:t2bot.io
test

This room is already a portal room.

Unknown command. Try !tg help for help.

This is a portal room: you must always prefix commands with !tg. Management commands will not be sent to Telegram.

General

cancel - Cancel an ongoing action (such as login)
help - Show this help message.

Authentication

ping-bot - Get the info of the message relay Telegram bot.

Creating portals

bridge [id] - Bridge the current Matrix room to the Telegram chat with the given ID. The ID must be the prefixed version that you get with the /id command of the Telegram-side bot.

Portal management

delete-portal - Remove all users from the current portal room and forget the portal. Only works for group chats; to delete a private chat portal, simply leave the room.
unbridge - Remove puppets from the current portal room and forget the portal.

Miscellaneous

sync-state - Fetch Matrix room state to ensure the bridge has up-to-date info.
id - Get the ID of the Telegram chat where this room is bridged.

This room is bridged to Telegram chat ID -1001190089799.

Please confirm unbridging chat "Data science at home" from room #telegram_datascienceathome:t2bot.io by typing !tg confirm-unbridge

Room unbridging cancelled.

Unknown command. Try !tg help for help.