I get the error, "I'm sorry, but you are not authorized to install Teamline."

Slack guest users

Note that Slack guest users aren't able to install apps. As a Slack guest user, you can send a direct message to @teamline within Slack, with just the word login

Teamline will then send you a link which you can use one time to login.

How to login without using the "Login with Slack" button

You can always login by sending a direct message to @teamline, inside Slack.

To do this, send a direct message to @teamline within Slack, with just the word login

Teamline will then send you a link which you can use one time to login.

How to pre-approve Teamline to work with everybody in your team

Depending on the way that Slack is configured, it's possible that Teamline may need to be approved by a team administrator or the team owner. 

To pre-approve Teamline to work with your team, you can visit http://slack.com/apps/manage and clicking the "Approve" button beside Teamline. This will allow your team members to login and use Teamline.