Media Converter (Converts video perfectly but no screenshot?)

We have a Primary Web Server (Core Files), 3 Direct (Remote) servers, and a MySQL DB server, We are able to get videos to convert, but screenshots are not showing, We have checked the file permissons for _Cache folder, but no contents are there, SSH details are in Local Default and all Direct Servers both in Admin Panel and in the convert.php file, along with SQL details. Conversion works great, but screenshots are not working. What would be the best way to determine the issue with this setup?

Also I noticed that the conversion also fails if I let the cron run on it's own, BUT when I run the cron manually it's successful.