Issues signing PDF documents with Hong Kong Post e-Cert

Hi,

Hope this is the right place to post...

I am trying to sign PDF documents with my newly issued Hong Kong Post e-Cert Digital Certificate.

This is in Acrobat Reader XI (11.0.07) on Windows.

I can sign the document OK - but when I review the "Signature pane" I see that the Signature is invalid:

Looking at the Signature properties I can see the following:

The chain of the Signature is:

- Hongkong Post Root CA 1

  - Hongkong Post e-Cert CA 1 - 10

     - WILSON Matthew James - my certificate

The Root and next level are trusted:

The error is "The selected certificate path has errors: Invalid policy constraint"

This certificate seems to have a policy:

Where as the Next Level and my certificate do not:

Is this the cause of the issue?

If so - is this something the issuing CA needs to sort out - i.e. Hong Kong Post or is a local configuration issue?

Many Thanks

Matthew