This is a copy of: https://confluence.atlassian.com/jirakb/can-t-uninstall-apps-after-cancellation-1369277736.html

Summary

If the uninstall button is grayed out, this means that your cloud instance is using Atlassian’s new cloud billing engine where the stop trial button is not available instead, there is a Manage subscription button where you can only cancel the app and you have to wait for the cancellation period.

Solution

To uninstall an app, you need to follow these steps:

• Click on the Manage Subscription button.

• You will be redirected to the Billing page for your cloud instance.

• Cancel the subscription for this add-on.

The app subscription will be canceled and scheduled for deletion after the cancellation period of 30 days.

Having said that, if you would like to immediately delete the subscription and not wait for the cancellation period, please contact the billing team where they can immediately delete the app subscription upon your request.