SIM Relay Response Timeout Error While Integrating Authorize.Net SIM Method using c#

While integrating Authorize.Net's SIM using c# into my web application i kept getting a timeout error while redirecting response to a response url. The error is as follows

Your script timed out while we were trying to post transaction results to it.
  Transaction ID: xxxxxxxxx
Transaction Result: This transaction has been approved.

The following message was displayed to the customer:

------------------------------An error occurred while trying to report this transaction to the merchant. An e-mail has been sent to the merchant informing them of the error. The following is the result of the attempt to charge your credit card.

This transaction has been approved.

It is advisable for you to contact the merchant to verify that you will receive the product or service.