HipChat::Unauthorized: Access denied to room {room name}
Something must have changed very recently, but it seems that you can no longer send messages to a room via personal v2 token. You have to generate a "room" level token.
The API situation with Hipchat is VERY confusing. The right place to generate this new token is under Group Admin -> Rooms -> {Your Room} -> Tokens
The url should look something like this:
https://{company}.hipchat.com/admin/rooms/tokens/{room id}