Plesk backup task finishes with the warning: Cannot stat: Permission denied

Symptoms

• Plesk backup task finishes with one of the following messages in Plesk interface:

  Failed to pack files example.com_user-data_1307261006 in /var/lib/psa/dumps/domains/example.com
  /bin/tar: httpdocs/components: Cannot open: Permission denied
  /bin/tar: Exiting with failure status due to previous errors

  ---

  Not all the data was backed up into /var/lib/psa/dumps/clients/cl_name/domains/example.com successfully.
  Mounted on: /. /bin/tar: .pki/nssdb: Cannot stat: Permission denied
  /bin/tar: Exiting with failure status due to previous errors

  ---

  Warning: Extension "Git"
  Unable to back up extension. Error: Failed to exec backup_restore_helper: Exit code: 1: filemng failed: mkdir: cannot create directory ‘/var/www/vhosts/example.com/.ssh’: Permission denied
  filemng: Error occurred during /bin/mkdir command.

  ---

  Warning: Subscription "example.com"
  Not all the data from /var/www/vhosts/example.com was backed up successfully:
  .cagefs/opt: Cannot open: Permission denied
  .cagefs/opt/alt: Cannot stat: Permission denied
  .cagefs/opt/alt/php56: Cannot stat: Permission denied
  .cagefs/opt/alt/php56/link: Cannot stat: Permission denied
  .cagefs/opt/alt/php56/link/conf: Cannot stat: Permission denied

• A backup restoration finishes with one of the following messages:

  Warning: Restore hosting "example.com"
  Can not deploy content of domain example.com
  warning:
  Archive error: Unable to extract files from /var/lib/psa/dumps/domains/example.com/backup_user-data_1907081210.tgz to /var/www/vhosts/example.com: /usr/lib/plesk-9.0/sw-tar: example.com/bin/gzip: Cannot open: File exists /usr/lib/plesk-9.0/sw-tar: example.com/bin/unzip

  ---

  Warning:
  Archive error: Unable to extract files from /var/lib/psa/dumps/domains/example.com/backup_user-data_1907311520.tgz to /var/www/vhosts/example.com: /bin/tar: httpdocs/some-picture.jpg: Cannot open: File exists /bin/tar: httpdocs/wp-content/uploads/2019/some-picture.jpg: Exiting with failure status due to previous errors

Cause

Incorrect permissions/ownership on the files and/or directories inside the subscription directory.

Resolution

1. Connect to the Plesk server via SSH.

2. Correct the file permissions:

   # plesk repair fs example.com -y

3. Restore the default ownership and permissions for /var/www/vhosts/example.com: according to the steps from this KB article.