Verify that the
atlassian-addons-admin group has the Jira Administrators permission, and that the
Jira Misc Workflow Extensions user belongs to that group.
Go to the Global permissions page (type gg then Global permissions)
Check whether the
atlassian-addons-admin group belongs to the Jira Administrators and Browse users and groups permissions.
If either of these checks fails, your Jira instance is not properly configured. You need to uninstall and then reinstall the JMWE add-on and check again. If the checks still fail, you need to contact Atlassian Support and ask them to fix these issues.
atlassian-addons-admin group is only visible on the Global permissions page, and not on the Groups and Users pages.