hi sashabogi, i see your log, the issue is related to background process (for fetching number of share on your post).
this background process come from JNews social share plugin. its cached for 24 hours. before it re fetched again.
i also notice your website is disabling social share. are you disable social share on purpose?
it seems your with those number of request, your server exhausted when requesting to other server (fetching share number).
do you want to disable this functionality? or do you want do disable the plugin all together?