I have updated version of reverse-proxy-auth-plugin to latest version 1.5, after update it tried to restart Jenkins via UI and is throwing error as mentioned in attachment.

I tried to restart Jenkins instance via http://<jenkins-url/restart , but still getting same error.

Even, I tried to remove reverse-proxy-auth-plugin related files from #[jenkins-home]/plugins/reverse-proxy-auth-plugin and restart but it didn't worked.