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 project/s, please follow this few steps.
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” subtab.
Make sure that you check the box for “issue tracking” to enable it in that project.