openWebResource( ) NOT working in Customer Service Hub

Hi,

I have a custom button on Contact form ribbon, which opens a webResource.

JS used is: -
Xrm.Navigation.openWebResource("CustomPage.html?id=" + recordId, null, 1100, 800);

- This works fine from Sales --> Contacts --> Contact screen.

URL generated is https://crmdomainname.com/%7B636917960880004041%7D/WebResources/CustomPage.html?Data=1100&appid=9b4509cd-0603-e911-a952-000d3a45413b&id=%7b7C951744-B709-E911-A952-000D3A454977%7d

But when in Customer Service Hub, the same form is opened and the ribbon button is clicked then error in popup window appears: -

HTTP Error 500 - Internal Server Error

URL generated is https://crmdomainname.com/main.aspx?appid=ffa4baf2-0603-e911-a952-000d3a45413b&pagetype=webresource&webresourceName=CustomPage.html%3Fid%3D%7B7C951744-B709-E911-A952-000D3A454977%7D&data=1100&cmdbar=false&navbar=off

Same JS is called to generate the URL in both the cases.
Xrm.Navigation.openWebResource("CustomPage.html?id=" + recordId, null, 1100, 800);

Any help here ?

Thanks,

Ajay