WCF time out issue

HI All,
I have set WCF timeout as 10 mins for both service and client application (closeTimeout="00:10:00" openTimeout="00:10:00" receiveTimeout="01:00:00" sendTimeout="00:10:00"), But it is throwing time out exception by 3 mins (02:59). Not sure the reason why it is happening.

Any solutions or ideas are appreciated!!