Seems like someone removed active plugins of configMgr from [1]. To enable steps are below assuming you have not done any other configuration changes at framework level.
- In crxde light open the config file starting with "org.apache.felix.webconsole.internal.servlet.OsgiManager" at /apps/syste/config/
- For plugins multified sting array value add "Configuration"
- Save the changes and verify.
Alternatively If it is local environment shortcut would be stop the instance , rename <cq_home>/crx-quickstart/launchpad and start the instance. Please do not try this on production before consulting from official support team.
If above does not solve there are other possibilities & request to file a support request.
[1] http://Host:Port/system/console/configMgr/org.apache.felix.webconsole.internal.servlet.OsgiManager