Some of our customers have issues with Ezoic CDN -- when its traffic gets graylisted or blocked in another way. To workaround this, we provided the special option trust ezoic. To enable it, open /etc/imunify360-webshield/virtserver.conf, find the directive

set $trust_ezoic 0;

replace 0 with 1, save the file and restart the webshield. After this all traffic having X-middleton substring in its User-Agent header will be proxied to destination without further ado.
When theres no more need to trust Ezoic traffic, just replace 1 to 0 in the aforementioned webshield directive and restart the webshield.
Please keep in mind that the matter of trusting Ezoic traffic is responsibility of a hostss admin entirely.