WordPress Plugins:

WordPress plugin problems usually happen for just a few reasons:

    The plugin is not compatible with your current WordPress version
    The plugin conflicts with other plugins, or the other way around.
    The plugin is updated but your WordPress version is not.

WordPress Themes:

WordPress theme problems usually happen for just a few reasons:

    The theme is not compatible with your current WordPress version.
    The theme is conflicting with a plugin you have installed or the other way around.
    The theme is updated but your WordPress version is not.
    You have tried to be clever with your theme or followed a tutorial that instructed you to place some code into your theme or the theme's function.php file.

A simple tip from
Ultimatecine.com