Technical user is a local JIRA user created in user management. On this user behalf:
There are few pitfalls here, so please double check this:
1. It will test your Server URL. It might happen that your JIRA Server has complex routing, so URL (JIRA Base URL) accessible from internet is different than local URL, which your server can access itself. Please check and eventually modify your Alternative JIRA Server URL in general configuration.
2. It will test if you have provided proper password for your user. This information can be due two reasons: