Can you try giving iframe src as
instead of full URL?
I already did but to not avail !!!!!!
The reason is in the hosting company.
Try to prepare iframe using an app hosted on your server or on apex.oracle.com, it will works fine...
It has nothing to do with hosting company. The problem is in authentication. IE can show in iframe only Login Page (www.domain.com/apex/f?p=app_number:101).
If you intent to show in iframe a Home page of Apex application (www.domain.com/apex/f?p=app_number:1) or any other page, error occurs.
I made a test and the same error occurs on MaxApex hosting as well as on apex.oracle.com .
Application which doesn't need authentication (No Authentication / using DAD), shows o.k. in iframe.
In this case remove also logout link (upper right corner) otherwise clicking on it will lead to IE error as well.