An error (The request was aborted: The request was canceled.) occurred while transmitting data over the HTTP channel.

I was getting an error "An error (The request was aborted: The request was canceled.) occurred while transmitting data over the HTTP channel." when I was trying to upload / stream large file through WCF Service, the file I was using is of more than 4 MB.

When we sent small files through the service, all worked fine. However, larger files (about 4MB and higher) generated the very unhelpful http exception: (400) Bad Request. This exception occurs because the entire message is not processed.

We looked at the typical culprits of this problem like <binding> settings such as maxReceivedMessageSize and <readerQuota> values to no avail.

It turned out the real problem was not in WCF, but in IIS. HTTP communication has a size limit that you have to override if you want to send large messages to your WCF service hosted in IIS. In the config file (web.config), adjust the <httpRuntime>‘s maxRequestLength attribute to a large enough size to support your messages. The value will be an integer representing the size in Kilobytes and has about a 2GB limit. The setting looks something like this (I set mine to about 64MB):
< system.web>
       <httpRuntime maxRequestLength="65536" />
< /system.web>

If IIS is the problem, you should now be able to process messages up to the size indicated in the maxRequestLength attribute.