title: Authorize.net : The underlying connection was closed
body: <p>I am working on a project where I am using Authorize.Net for payment processing.</p>
  
  <p>It was working fine, but today I am continuously getting an error "<strong>The underlying connection was closed: An unexpected error occurred on a send.</strong>" while calling any API function. Is this issue belong to authorize.net side?</p>
  
  <p>I am working on test mode using sandbox account.</p>