Scheduled backup fails: "Transport error: unable to list directory: Curl error: (67) Login denied: Last FTP response: 530 bad login"

Symptoms

• When creating or restoring a backup, the following message is sent to the Plesk administrator with the following error:

  PLESK_ERROR: The following error occurred during the scheduled backup process: Transport error: unable to list directory: Curl error (67) Login denied: Last FTP request: ***** Last FTP response: 530 bad login.

• The following errors occur during a scheduled backup in /usr/local/psa/PMM/logs/migration.log:

  CONFIG_TEXT: INFO: Unable to get backup info from dump header: Curl error: (67) Login denied: Last FTP request: PASS *****: Last FTP response: 530 bad login

  CONFIG_TEXT: INFO: TransportError[6a746e33-6872-401c-8611-208e2af91e0d]: Transport error: unable to list directory: Curl error: (67) Login denied: Last FTP request: PASS ***** Last FTP response: 530 bad login [./transport.cpp:824]

• Backup is still completed successfully as the login was possible after several failed login attempts.

Cause

Connection issues on a remote FTP server.

Resolution

Check logs on a remote FTP server to resolve a connection issue.