Unable to display SharePoint pages from a different domain in iFrame
Original KB number: 4531668
Summary
An error occurs when loading SharePoint pages inside an iFrame that originate in a different domain.
More information
This behavior is by design. Loading pages in this manner doesn't work because the HTTP header property X-FRAME-OPTIONS
is set to the value SAMEORIGIN.
Overriding this property by setting the web part to AllowFraming isn't recommended for security reasons. There are several functionalities that won't operate correctly when loaded into iFrame. (This behavior varies from browser to browser.)