fedex api for php

I am using FedEx api I have created the my acc开发者_运维问答ount on FedEx.

My problem is that when I am using test account number and test meter number I am getting the results properly, but when I am using client account detail I always get the error invalid header (invalid header).

When I have contact with the FedEx team, they said me to use different URL ( before asking with support team I am using this URL https://gatewaybeta.fedex.com/GatewayDC now they have asked me to use this URL gateway.fedex.com:443/gatewayDC ) but still the same response

Does one have any idea about this or have any API regarding FedEx shipping charge. I have to to find only shipping rate with this API