I have a single domain name pointing to a single server running a JoinFaces + PrimeFaces project. When I click on a p:commandButton in a form on the server through its IP address, then everything works just fine. But when I do the same through the domain name (instead of the IP address), I get the ERROR: MAC did not verify / javax.faces.application.ViewExpiredException error. Any idea why the server would be behaving differently based on whether it is accessed through its IP address or through its domain name?
The issue turned out to be related to an aggressive caching configuration in CloudFlare (i.e., including the view state).