jenkins Access Denied- asdf@gmail.com is missing the Read permission
You will have to reconfigure your permissions. Do you still have a user with login access or not ? If not you might have to reset it by temporarily disabling the security. This can be achieved by modifying the $JENKINS_HOME/config.xml ($HOME/.jenkins/config.xml by default when running the jenkins.war on your system) and setting <useSecurity> from true to false. Be sure to backup your config!
Once you are there reenable the security, and show us what you have in matrix and role based security.
Had the same issue with Jenkins, turns out my user name was Gideon but error I was getting was 'gideon is missing the overall administer/register permission'. Edited config.xml by changing Gideon to gideon in the /hudson/authorizationStrategy/permission tags and everything is working fine now.