Allowed memory size of 268435456 bytes exhausted (tried to allocate 72 bytes) ? That means your Memory Limit is 256MB. This maximum value is set by your host in master settings. So you will not get more than that even if you set 1000MB ! This is not a Theme Issue. This is a Hosting Resource Issue.
The most resource hungry part of NewsPress Font Page is Gallery Block. If you have a low resource Hosting, please Turn the Gallery Block OFF from WP-Admin > Appearance > NewsPress Options > Gallty
We believe that your Home Page will run normally. Or you may request your host to increase the limit to 512MB from Master Setting