Fatal error: Uncaught Error: Call to undefined function wp_generate_password()

class-boldgrid-backup-premium-admin-historical.php

<?php

// THIS IS THE ORIGINAL LINE, CAUSING THE PROBLEM:

$this->dir = Boldgrid_Backup_Admin_Utility::trailingslashit( $backup_dir ) . $base_dir . wp_generate_password( 16, false );



// THIS IS THE FIX TO THE PROBLEM:

/*
 * Generate a 16 character key to help make the "historical" directory name unique.
 *
 * Originally we used the wp_generate_password function to do this, however a report
 * came in of a fatal error when this function was undefined:
 * https://wordpress.org/support/topic/fatal-error-blocked-me-from-wp/
 *
 * There are other methods to create a random string, such as time(). However, to keep
 * backwards compatibility, the random string MUST be 16 characters long.
 */
$random_key = substr( md5( time() ), -16 );
$this->dir = Boldgrid_Backup_Admin_Utility::trailingslashit( $backup_dir ) . $base_dir . $random_key;

?>