From 1.7.0 version the add-on supports integration with multiple TeamCity servers. For each TeamCity instance, you need to have an individual application link.
The primary application link to TeamCity server does not affect anyhow functionality or order of the add-on operation.
1. Navigate to JIRA > Administration > Add-ons and open the Application Links section.
2. Enter address of TeamCity instance and click Create new link.
If you see the form with notification about invalid URL address, just skip it by clicking Continue.
3. After verification of TeamCity instance, the Link Applications form is displayed.
4. In the Link Applications form, specify the following information:
5. Leave all the other parameters without any changes.
6. Click Continue.
7. A new application link will appear on the list with available application links.
8. Click the Edit link to modify access parameters.
9. In the opened Configure Parameters form, switch to Outgoing Authentication.
10. Here enter credentials of TeamCity account with assigned Project Viewer and Agent Manager roles.
11. Click Enable and Close the form.