Pop-over: Cannot Open Page

During a phone call, you cannot surf the web, and this is the message that appears when you try.

Cannot Open PageSafari cannot open the page.
The error was: "A data connection cannot be established since a call is currently active.".

Note: The punctuation is correct, there is a period inside and outside of the final quotation mark.  

Recommendation: Include another button that allows the user to end call or allows the user to switch to the phone app.