MS Dynamics 365 Online Plugin External Rest API access gives error - plugins

Question

I am trying to access an external third party API from a Dynamics 365 Online plugin using the following code:
public void Execute(IServiceProvider serviceProvider)
{
//Extract the tracing service for use in plug-in debugging.
ITracingService tracingService =
(ITracingService)serviceProvider.GetService(typeof(ITracingService));
try
{
tracingService.Trace("Downloading the target URI: " + webAddress);
try
{
//<snippetWebClientPlugin2>
// Download the target URI using a Web client. Any .NET class that uses the
// HTTP or HTTPS protocols and a DNS lookup should work.
using (WebClient client = new WebClient())
{
byte[] responseBytes = client.DownloadData(webAddress);
string response = Encoding.UTF8.GetString(responseBytes);
//</snippetWebClientPlugin2>
tracingService.Trace(response);
// For demonstration purposes, throw an exception so that the response
// is shown in the trace dialog of the Microsoft Dynamics CRM user interface.
throw new InvalidPluginExecutionException("WebClientPlugin completed successfully.");
}
}
catch (WebException exception)
{
string str = string.Empty;
if (exception.Response != null)
{
using (StreamReader reader =
new StreamReader(exception.Response.GetResponseStream()))
{
str = reader.ReadToEnd();
}
exception.Response.Close();
}
if (exception.Status == WebExceptionStatus.Timeout)
{
throw new InvalidPluginExecutionException(
"The timeout elapsed while attempting to issue the request.", exception);
}
throw new InvalidPluginExecutionException(String.Format(CultureInfo.InvariantCulture,
"A Web exception occurred while attempting to issue the request. {0}: {1}",
exception.Message, str), exception);
}
}
catch (Exception e)
{
tracingService.Trace("Exception: {0}", e.ToString());
throw;
}
}
}
But I am getting the error:
Request for the permission of type 'System.Security.Permissions.SecurityPermission, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.'
I have checked MS documentation but nothing suggests why I am unable to do this. I know about sandboxed plugins but according to MS I should be able to do this using their own sample code.

Answer 1

This is expected in CRM Online, as this is SaaS and you're in a shared tenant in cloud. You can do either webhook or Azure service hub to trigger external endpoint with CRM context for processing. Read more
And if you've got CRM Online, then the normal solution is to offload the processing to an environment that you have more control over. The most common option is to offload the processing to Azure, using the Azure Service Bus or Azure Event Hub. The alternative, new to CRM 9, is to send the data to a WebHook, which can be hosted wherever you like.