Unable to create or restore backup on Plesk server: Can't find public key in database

Nikita Zubovich

Updated November 09, 2023 07:17

Plesk for Windows Plesk for Linux kb: technical ext: migrator

Applicable to:

Restoring a backup fails with the following error:

PLESK_ERROR: Error: backup_sign: Can't find public key in database:
backup_sign: Can't get server's public key
The following error occurred during a scheduled backup:

PLESK_ERROR: Unable to create remote backup. Error: Unable to export backup: Can't initialize RSA private key
Backup or migration finishes with a warning:

Warning: Unable to upload the backup to the FTP storage: Unable to set backup sign certificate
Migration pre-check shows the following warning:

CONFIG_TEXT: stderr: rsync: link_stat "/root/plesk_migrator/plesk_migrator-9xcxzh5oqyrrqyfdhjs8dezlk536xa5p/backup.tar" failed: No such file or directory (2)
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1650) [Receiver=3.1.2]
rsync: [Receiver] write error: Broken pipe (32)

The following error can be found in the /var/log/plesk/panel.log on a target Plesk instance:

ERR [1] ERROR: Call to a member function delete() on null (BackupSignCertificate.php:35)

Backup sign certificate is missing.

Note: if you don't have root access to Plesk server via SSH/RDP, contact your hosting provider regarding the issue

For Linux:

Connect to the server via SSH.
Regenerate the backup sign key using below command:

Note: if the issue occurred during migration, run the command on the source server

# /usr/local/psa/admin/sbin/backup_sign --generate
Restore, create a backup, or re-run the migration again.

For Windows: