Ok you have isolated the problem to the BPS Pro root .htaccess file by doing this using a manual method instead of using the BPS Pro troubleshooting steps, which is fine if that is the way you prefer to troubleshoot things.
What this means is that you need a Plugin skip/bypass rule for this plugin in your root .htaccess file.
Do these steps:
1. Copy the code below to this BPS Root Custom Code text box: CUSTOM CODE PLUGIN/THEME SKIP/BYPASS RULES
Note: If your WordPress installation is a subfolder installation then add your WordPress folder name in the path. Example: /My-WordPress-Folder-Name/wp-content/plugins/video_jacker/
# Video Jacker plugin skip/bypass
RewriteCond %{REQUEST_URI} ^/wp-content/plugins/video_jacker/ [NC]
RewriteRule . - [S=13]
2. Click the Save Root Custom Code button.
3. Go to the BPS Security Modes page, click the Create secure.htaccess File AutoMagic button and activate Root folder BulletProof Mode.