Error in check out

hi nopComerce community, i encountered this error message while making a test purchase on my site:

Request for the permission of type 'System.Net.WebPermission, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.

thanks  for the help

You have some right issues here. But the details about the error are not in your post.
What trust level are you running in?
At what step did the error occur?
And, because you have posted this in development topic, what did you change?

the error msg appeared at the Order Confirmation section of the checkout process (checkoutonepage.aspx) after all customer data were collected.   i am using actual Authorize.net payment method information.  

the changes i've made were only at the product-details page where i combined some user controls.

running on full-trust

thanks