Unable to update Plesk/Install components: Unable to create yum cache for ‘*epel’ OS repository.

Symptoms

• The following error message is displayed in Plesk installer during installation/update:

  Enabled repositories check
  Unable to create yum cache for '*epel' OS repository.
  Make sure the repository is available, otherwise either disable it or fix its configuration, then try again.

• Epel repository is set up correctly

Cause

Corrupted yum cache

Resolution

1. Connect to a Plesk server via SSH.
2. Back up the current cache:

   # mv /var/cache/yum/x86_64/7/ /var/cache/yum/x86_64/7_back

3. Clean the cache:

   # yum clean all