msix signing errors and solutions with EV code signing certificates

When signing .msix packages using an Extended Validation (EV) code signing certificate, you may encounter an error caused by certificate subject fields that do not match the package manifest.

This issue is caused by how Microsoft's signing tools handle the strict subject requirements enforced by the CA/Browser Forum’s EV guidelines.

To troubleshoot and to avoid signing errors, use Microsoft’s ModifyPackagePublisher script to update the .msix package metadata with properly encoded OID values that match your certificate’s subject.