OWA Advanced Customization Template - Password Change

Dear,

we have a logon page for OWA customized following the advanced customization guide : https://devcentral.f5.com/wiki/APM.APM-Advanced-Customization-Templates.ashx

But when a password is expired, the APM does not prompt for the change password page, and go back to the logon page again. I see in the log the following error "

AD module: change password for 'username' failed: Password change rejected(4)

"

I took a capture and the AD returns the error STATUS_PASSWORD_MUST_CHANGE as expected.

It works fine with the default logon page with the same username and the same AD. we're running version 11.5.1

Could you please advice on what could be missing in the template?

Thanks.