Email Approval Response Feature Does Not Work in Salesforce Approval Process

This issue occurs when the approver replies to the wrong email address. The Email Approval Response feature works only when the approver responds to the long computer-generated email address that appears in the "To" field when clicking Reply on the Approval Assignment Email Template email. If the approval email was not sent from the correct template, the reply goes back to the sender rather than the approval engine.
Follow the steps below to verify the configuration and resolve the issue.

Verify the Reply-To Email Address

1. Open the approval request email in your email client.
2. Click the Reply button.
3. Check the To field. If the feature is working correctly, the To field shows a long, computer-generated email address (the Email Approval Response service address). If it shows the sender's email address instead, the wrong email template is configured.

Correct the Approval Assignment Email Template

1. Navigate to Setup.
2. In the Quick Find box, enter Approval Processes and select Approval Processes.
3. Select the relevant object and click the Approval Process name.
4. Locate the Approval Assignment Email Template field and ensure it is set to the correct template that generates the computer-generated reply-to address.
5. Save your changes.

Prerequisites

Before using Email Approval Response, confirm the following:

• Enable Email Approval Response must be enabled in Setup so that the long computer-generated email address is visible when replying.
• The Receive Approval Request Emails field on the Approver's User detail page must be set to either If I am an approver or delegated approver or Only if I am an approver. It must not be set to Never.