# mbc auth The `mbc auth` command can be used to log into Matrix accounts. To log in with `mbc auth`, first make sure you have your homeserver listed in the `homeservers` section in the maubot config (the secret can be empty). If you haven't used the `mbc` tool before, log into your maubot instance with `mbc login`. Finally, run `mbc auth` and fill in the parameters: * The homeserver is the dictionary key, i.e. server name (not URL) from the `homeservers` config. * The username can be either the username or full user ID, that doesn't matter. * The password is the password. If the command says "Registration target server not found", it means you didn't add the server to `homeservers` properly or didn't enter the correct name in `mbc`. If you want to register an account, you must pass `--register` as a parameter. This also requires the `secret` to be set in the config. Single sign-on is also supported by using the `--sso` flag. When that flag is passed, the command will open the login page in a browser instead of prompting for username and password. Additionally, there's a `--update-client` parameter that tells maubot to store the created access token as a client instance so you don't have to do it manually in the web interface.