Within Teamwork Chat, when you are logging in, some of your associated accounts may come up as inaccessible.
An account could be inaccessible if Teamwork Chat is not enabled for that particular installation.
To enable it, go to the site settings in your Teamwork Projects account, and select the Integrations tab:
Here, you will see an option for enabling Teamwork Chat:
Note: If the Chat integration is disabled, it won't be accessible for any of your users.
For more information, see: Accessing your Teamwork Chat site