If you have such a problem when you activate your WordPress theme, chances are that there is a server/code error. This could mean the following:

1. There is a theme code error
2. There is a server error, most probably a PHP version error.

Most themes now require at least PHP5.6 to run on your server in order work properly, as previous versions of PHP are being discontinued: http://php.net/supported-versions.php

In case you are sure that your server meets the requirements of the theme/plugin you have installed, please try to activate WP_DEBUG in order to see where it the error coming and then check the line of code/fix it.

In our case, please send the screenshot/error code to our support staff and they will assist with getting things fixed.