A client windows application is calling a web service method to upload images to a server. The images are serialized as bytes via XML in a SOAP message. At various times during the day the call to the web method is returning "The request failed with HTTP status 404: Not Found.". My initial thought was that it is caused by network connectivity issues, where the client is unable to connect to the web service when it needs to. But then I did a further analysis and saw that the error message is only returning if there are on average 20 or more pages being uploaded with the call. Calls with a low number of pages do not have the issue. This makes me think that perhaps the issue concerns bandwidth, so that if there is too much data being sent with the call then it is being rejected. But why this 404 message? Can someone tell me what this means? I can provide more info if needed.