What you have to do.

1. Login to your isUp.li account and choose “Slack”.
   
2. That’s your slack connections. Click the “+ Add” button.
   
   
3. Click the “# Add to Slack” button.
   
   
4. Confirm your identity and choose where to get the notifications (“Post to”). Authorize.
   
   
5. If all went well, the Slack WebHooks-URL filled in automatically. Choose a name for your connection. Check.
   
   
6. If check went well add your new connection by clicking on “Add”.
   
7. In your isUp.li Server Manager edit your server settings and choose your Slack connection. Save.
   
   
8. You’re done. 🙂