[Plugin: 404 Redirected] 403 Forbidden

Sound like a folder permissions problem.
Check if the plugin folder and subfolders (also the wp-content and wp-content/plugins folder) is set to 755.
If it is temporarily change plugin folder permissions to 777 (just to test!)
Also look for any htacces files in the plugin folder – There shouldn’t be any htacces in the plugin folder unless one has been created on purpose.