417 expectation failer error

I got an error message saying 417 expectation failer error,what should i do now? 

I never see this error in my life as it nearly never comes in browser as today servers are so fast and intelligent they cant deal it very carefully and nicely.But we must be aware of it what it is saying to us it means that what header entities are given by the use agent to server ; they are not expected by the server and they are ambiguous and unambigous ways to deal it.

The server cannot meet the requirements of the expect request header field.there may some proxy server that may prevent this to do.

In this case, you must contact your server administrator to solve your problem, otherwise this would be prevailing