Wp-calypso: View Site: Infinite Scroll doesn't load when site has a custom domain

[liviopv]

Steps to reproduce

1. Open a site with a custom domain, infinite scroll active, and more than 7 posts on Calypso
2. Click on View Site
3. Scroll down the site until it reaches the first infinite scroll breakpoint (usually 7 posts)
4. The infinite scroll will fail and it will start to "flick"

What I expected

The preview should continue loading posts if there are posts to load, like it does for sites without custom domains.

What happened instead

The preview fails to load any posts after the first infinite scroll breakpoint and starts flicking.

Browser / OS version

I tested on:

OS: macOS 10.12.6
Browsers: Chrome 61.0.3163.100, Safari 11.0, Firefox 54.0.1

Screenshot / Video

Video: https://cldup.com/YPCAI1oigl.gif

Javascript console errors: https://cldup.com/Bfc6ROB82T.png

Context / Source

user-report

[lancewillett]

I'm able to repeat this on lance.blog using Safari 11.0.1 on OS X 10.12.6 — logged in to Calypso, clicking View Site.

Once I scroll to the bottom of the preview — past the first set of posts (7 posts), the 8th post appears but nothing more. And I see the "flickering" as well.

Console JS errors:

Failed to load resource: Origin https://lance.wordpress.com is not allowed by Access-Control-Allow-Origin. XMLHttpRequest cannot load https://lance.blog/?infinity=scrolling due to access control checks

[lancewillett]

A fix for this is in the works, see D9581-code.

[jblz]

@lancewillett When you have a sec, can you please try https://wordpress.com/view/lance.blog for me & make sure infinite scroll works there and on the frontend?

The fix is in place server-side.

[lancewillett]

Works as expected! Yay!

Still works on wpcom subdomains also: testing with https://wordpress.com/view/lancetest14.wordpress.com

[jblz]

I'm going to go ahead and close this.

If anyone has any specific cases where this isn't working, please feel free to reopen or create a new issue.

[Shavindra]

Hi @jblz

We are having issues too http://gems.trurating.com/

[jblz]

We are having issues too http://gems.trurating.com/

Hi @Shavindra. Thanks for the report. Let's see if we can figure it out.

It looks like that site is using an Azure Rewrite App or something similar. Can you confirm? Also, what kind of issues? Is infinite scroll not working in View Site or is the section not working altogether?