For some reason the Admin Tools GeoIP plugin has a conflict with another extension called Asikart Local & Remote Media Manager which is a Joomla media manager replacement. The following error is displayed when a user tries to access their media manager.
Fatal error: Call to undefined method Composer\Autoload\ClassLoader::setPsr4(),
The developer of the extension says that the issue is caused due to an old composer ClassLoader version. You can read it below or at the following url: https://github.com/asikart/remoteimage/issues/19
"It because the System - Akeeba GeoIP provider plugin use old composer ClassLoader version, and quickicons use the new version so they are conflict.
Please remove Akeeba GeoIP or rename it's folder, and ARI will working fine."