Integrating App in SaaS but I get empty page

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Hi Experts,

I did extension to the FA. In Sandbox before publishing was working fine. but when publishing to production. I get empty page.

I noticed when I keep the VBCS logged in the same browser. The page works fine in production. complete functionalities work smoothly.

Do you have a solution for it.

It looks like I am allowing it to work only when I am logged in to VBCS instance.

The empty page shows only the background and the text.

But the template is not appearing which is the landing page. Only when I log in it appears after reloading the page.