When using Sitecore Email Experience Manager on Azure PaaS, you might run into the error:
System.Net.WebException
Message: Unable to connect to the remote server
An attempt was made to access a socket in a way forbidden by its access permissions 127.0.0.1:80
The cause of this error, is that Sitecore tries to display the message by making a call to localhost. However, connection attempts to local addresses (e.g. localhost, 127.0.0.1) and the machine’s own IP will fail on Azure.
To get around this, you should set
<setting name=”EXM.RendererUrl” value=”https://onelittlespark-cm.dev.com” env:require=”Development” />