Can't activate JIRA Issues on Ultimate Trial

Can’t activate Jira Issues on Ultimate Trial

Trying to test out GitLab’s integration with JIRA, and ran into an issue: The “Enable Jira Issues” toggle is greyed out with a link to purchase Premium beside it:

I understand that this is a Premium feature (which is the level I’m currently planning to go with), but the trial was setup with Ultimate which should include everything in Premium. The JIRA link is setup and enabled according to this guide: Jira DVCS connector | GitLab