Origin errors are typically caused by either a mismatch in DNS records or the SSL setup between your original setup and the Ezoic setup, or by the host or a security layer blocking requests going via Ezoic servers.
Here are some checks you can make:
1. DNS Records
Check that the DNS records at your host match those you have entered at Ezoic.
A way you can check the IP we have in Ezoic is correct is to check at your host. Or you can also check this is by editing your host file to connect to the IP you have in your Ezoic dashboard.
If you can edit the host file and connect to the origin server IP without an error then the IP we have for your site at Ezoic is likely correct.
This would then mean the error is likely coming for your host blocking requests. in which case you should implement the solutions found in the guide i shared above.
Check your Ezoic SSL is setup correctly.
Try changing it to flexible it may work for your site.
3. Security Plugins
It may also come from the security plugins you are using.
If you disable them and the error is removed then the plugin will have been blocking requests. You can either keep this off or whitelist Ezoic Ips in the plugin. You can see how to do that here: https://support.ezoic.com/kb/article/how-to-fix-origin-errors