Iframe cross origin error on all browsers

[csspro]

I am getting the following error in Chrome (and a similar one in other browsers):

Uncaught DOMException: Blocked a frame with origin "https://www.abcxxx.com" from accessing a cross-origin frame.

I tried changing X-Frame-Options in my web.config file from SAMEORIGIN to ALLOWALL, but it didn't help.

Thanks.