Unable to set the private key in Plesk for Linux: Probably, the private key format is invalid

Symptoms

• Certificate uploading to Plesk fails with error:

  PLESK_ERROR: Unable to set the private key: Probably, the private key format is invalid

• Private Key in the .key file contains the following string:

  CONFIG_TEXT: -----BEGIN ENCRYPTED PRIVATE KEY-----

• The following error message appears in the Plesk logfile /var/log/plesk/panel.log:

  CONFIG_TEXT: ERR [panel] Unable to set the private key: Probably, the private key format is invalid.

Cause

Certificate Private Key part is encrypted.

Resolution

1. Connect to the Plesk server via SSH.

2. Upload a .key file to the server.

3. Decrypt the .key file using the openssl utility:

   # openssl rsa -in my_encrypted.key -out my_decrypted.key

   where:

   • my_encrypted.key - is an uploaded file from step 2
   • my_decrypted.key - a decrypted file that will be created

   Note: To decrypt the key, a passphrase that was entered upon creating the key is required. It will be requested by openssl.

4. Use the new decrypted .key file (In this example, my_decrypted.key) to upload an SSL certificate in Plesk.