Try installing a fresh copy of WordPress. If that works, the clone mainly fails due to server memory limitation or PHP / Webserver timeout.

Try uploading the backup file to your server and use the link to your backup file It reduces the downloading time of the backup.

Increasing memory limit of the destination server would help resolve 500 error / memory exhaust error.

If the clone appears to be incomplete kindly increase the PHP / Webserver timeout of the clone.