UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.95 Safari/537.36

Steps to reproduce the problem:
1. I have a website say domainone.test.com which has an iframe for the subdomain domaintwo.test.com
2. in iframe I have a image file which upon clicking opens up a new tab with the pdf file URL.
3. In newly opened tab request just goes file and i receive the expected response but it fails to render the pdf. I checked the dev tools console it does not report anything.
3. If instead of the iframe hosted in domainone.test.com, if i open the domaintwo.test.com directly in chrome and repeat the same thing it displays the pdf correctly in browser

What is the expected behavior?

What went wrong?
Not sure I am guessing it is something to do with CORS but browser does not complain anything in request response cycle. It just the chroms's default pdf renderer which fails to load the pdf file

Did this work before? No 

Does this work in other browsers? Yes

Chrome version: 55.0.2883.95  Channel: stable
OS Version: OS X 10.10.5
Flash Version: Shockwave Flash 24.0 r0