All of my wordpress websites on cyberpanel suddenly shows error 503

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2

Welcome @vishaljethwani Happy you are here

  1. Are you using modsecurity ? Disable it and try again

  2. Probably you reached max children process limit. You can confirm this by checking /usr/local/lsws/logs/lsrestart.log to fix this just restart lsws service

$ systemctl restart lsws || service lsws reload

This means you might be having so many php processes running you will need to run High CPU Usage, 4CPU 8GB RAM - #19 by josephgodwinke

Makes sure to run upgrade script and reboot your server