What causes "Application email ("%s") has an invalid default author ("%s")." in phacility/phabricator?

Edit the application email and reassign the default author to an existing, active user.

phacility/phabricator · error · Exception

Application email (" ") has an invalid default author (" ").

Error message

Application email ("%s") has an invalid default author ("%s").

What it means

The application email does have a default author PHID, but PhabricatorPeopleQuery could not load a user for it. This is a plain Exception (an internal configuration invariant, not a usage error): the stored default author references a user that no longer exists or is invisible to the loading viewer, so every mail to this address will fail processing.

Solutions

Edit the application email and reassign the default author to an existing, active user.
Verify the stored PHID resolves: look the user up by PHID in the People application.
Audit other application emails for the same dangling default-author reference.

Defensive patterns

Strategy: validation

Validate before calling

// Validate the default author resolves before relying on the address:
$author = id(new PhabricatorPeopleQuery())
  ->setViewer(PhabricatorUser::getOmnipotentUser())
  ->withPHIDs(array($application_email->getDefaultAuthorPHID()))
  ->executeOne();
if (!$author) {
  // alert an administrator: dangling default author on this application email
}

Prevention

When deleting users, check for application emails referencing them as default author first.
Re-set the default author after user renames/imports.
Run a periodic audit query comparing stored default-author PHIDs against the user table.

When it happens

Trigger: The default-author user was deleted after being assigned to the application email; the PHID was edited/imported incorrectly; the user exists but is not loadable by the processing viewer.

Common situations: Account pruning when staff leave; data imports that preserve application emails but not user rows; manual PHID edits in the database.

Related errors

AI-assisted analysis of phacility/phabricator@5720a38cfe (2026-08-21). Data as JSON: /api/errors/191950b4ec7e50bc. Report an issue: GitHub.

Appendix: source

Thrown at src/applications/metamta/receiver/PhabricatorApplicationMailReceiver.php:75

        // You either need to be sending from a real address or be sending to
        // an address which accepts mail from the public internet.

        if (!$author_phid) {
          throw new PhabricatorMetaMTAReceivedMailProcessingException(
            MetaMTAReceivedMailStatus::STATUS_UNKNOWN_SENDER,
            pht(
              'You are sending from an unrecognized email address to '.
              'an address which does not support public email ("%s").',
              (string)$target));
        }

        $author = id(new PhabricatorPeopleQuery())
          ->setViewer($viewer)
          ->withPHIDs(array($author_phid))
          ->executeOne();
        if (!$author) {
          throw new Exception(
            pht(
              'Application email ("%s") has an invalid default author ("%s").',
              (string)$create_address,
              $author_phid));
        }
      }

      $this
        ->setApplicationEmail($application_email)
        ->setAuthor($author);

      return true;
    }

    return false;
  }

  private function loadApplicationEmailList() {

View on GitHub (pinned to 5720a38cfe)