PHP

Disable any EOL (end of life) PHP versions on the server.

Keep tabs on that here.

In WHM -> Home -> Software -> EasyApache 4, click "Customize." In the left hand pane, click "PHP Versions." Deselect any EOL versions there. Then click "Review" and "Provision."

Still on EA3?  That's EOL at the end of 2018, you need to upgrade to EA4.