Sending Email as Guest User Fails When Profile Has Appropriate Permissions

As of the Summer '21 release, newly created Experience Cloud sites no longer assign the site administrator's real email address to the Guest User record. Instead, a system-generated fake email address is assigned. This change was made to prevent the accidental public exposure of internal email addresses.

Resolution Steps

To resolve this, update the Guest User record with a valid email address:

1. Go to Setup > All Sites and click Manage next to the affected Experience Cloud site.
2. Click the Guest User profile link.
3. Navigate to the Guest User record.
4. Update the Email field with a valid, real email address.
5. Save the record.
6. Re-test the email send operation.

Note:
A Guest User's email address is associated with an unauthenticated user account and is considered public information. Any email address assigned to the Guest User record may be visible without authentication. Only use email addresses that are acceptable for public visibility. Do not assign personal or sensitive internal email addresses to the Guest User record.