Because we have our own CA certificate authority in my company, using https for Jenkins update center wasn't possible (empty plugin list). I used the following guide (link) to add our certificates to JVM which resolved my "empty list issue"; but when trying to actually install one of the plugins I am receiving the following error:

{{java.io.IOException: Downloaded file /var/lib/jenkins/plugins/ccm.jpi.tmp does not match expected SHA-1, expected 'Begz4m+YT3VCEImnIOEg3/Dzi9s=', actual 'pWKXa4iUnlHx2iEAfRJYJLf3DVE=' }}