Please consider, these type of errors are not related with Themes. The error message may be even related to the amount of resources assigned to your hosting account in which case we can not reproduce it because it might be tied to the configuration of your server. Try to increase the memory limit of your WP Installation and Server. Installing Caching Plugin like w3 Total Cache and using the Free Plan of CoudFlare may optimize your site for better performance with limited resources.
According to some people this error message is related to cache plugin, so if you have one installed in your website go and flush/rebuild the cache and the problem will go away.
You can follow This Tutorial for NewsPress Gallery Settings.
