I have created an approval process on a custom object. I have also selected "Enable Email Approval Response" checkbox under "Workflow and Approval Process" settings. Everything works fine and approver gets notification email. He can simply approver record by replying back to that email. But the problem is that delegated approver of actual approver doesn't get this email. I need to notify delegated approver since actual approver is going on vacation. Is there any setting that needs to be enabled? Any thoughts?
We came across the same problem and, according to the article below, it's not possible.