If your Redmine integration keeps on getting disabled, it’s possible that one or some of your Redmine projects doesn’t support issue tracking. To make sure issue tracking is enabled in your projects follow the steps below:
Go to your admin account and individually visit each project. Once you’re inside a project, click on the settings tab and select the modules sub-tab.
Make sure that you check the box for issue tracking to enable it in that project and click save for changes to take affect.