Error 0x80080209 when signing appx file for Windows UWP

I have build a Windows 10 UWP cordova application, and are now trying to sign it. I already have a certificate that is used elsewhere (to sign .net assemblies) so I thought I would use the same one for this application signing.

When I use the signtool.exe, I get the following error..

SignTool Error: An unexpected internal error has occurred.
Error information: "Error: SignerSign() failed." (-2146958839/0x80080209)

Looking in the event log as suggested here, I see no errors just 2 information messages

The reader was created successfully without manifest validation.

I have made sure the Publisher fields in the AppxManifest.xml file matches the subject in the certificate.

Looking here, I see this described as

0x80080209-APPX_E_INVALID_SIP_CLIENT_DATA
Description : The SIP_SUBJECTINFOstructure used to sign the package didn’t 
contain the required data

Does anyone have any idea what this means?

[UPDATE1]

After the above failed, I attempted to create a new certificate as outlined here.

I used the following.

# create
New-SelfSignedCertificate -Type Custom -Subject "CN=My Company Pty Ltd, O=My Company Pty Ltd, C=AU" -KeyUsage DigitalSignature -FriendlyName mycert_uwp -CertStoreLocation "Cert:\LocalMachine\My"

 # get info
 Set-Location Cert:\LocalMachine\My
 Get-ChildItem | Format-Table Subject, FriendlyName, Thumbprint

 # export
 $pwd = ConvertTo-SecureString -String password123 -Force -AsPlainText 
 Export-PfxCertificate -cert "Cert:\LocalMachine\My\17BBBBBB2DC49F550671AF3E72120C88E2333333" -FilePath h:\0\mycert_uwp.pfx -Password $pwd

All appeared to work fine.

In my AppxManifest.xml I have...

<Identity Name="com.mycompany.myapp" Publisher="CN=My Company Pty Ltd, O=MyCompany Pty Ltd, C=AU" Version="1.0.1.1" ProcessorArchitecture="x86" />

I still get the same error when using the above.

[UPDATE 2]

The signtool command I am using is

signtool sign /fd SHA256 /a /f myapp_uwp.pfx /p may password c:\dev\myapp\platforms\windows\build\windows\release\x86\win10\Upload\CordovaApp.Windows10_1.0.1.1_x86\CordovaApp.Windows10_1.0.1.1_x86.appx

as outlined here.

I have also tried using SHA384 and SHA512. There is also the suggestions to try using the /debug and I get an error suggesting /debug is an invalid option.

[UPDATE3] It appears to be the certificate. I tried to use via Visual Studio (Packaging, Choose certificate), but get the following error (after entering the password)

.. and yets I have followed the instructions here (and triple checked).

Are these instructions wrong??

Just in case someone else had similar issue (0x80080209 error while signing), newer version of signing tool (the one from Windows 10 SDK) worked for me