IIS has a limit for the size of the files users can upload to an application. If the file size exceeds the limit, the application will throw “Error in HTTP request, received HTTP status 413 (Request Entity Too Large)” error.
The default file upload size is 49 KB (49152 bytes). The application records the log below if user tries to upload a file that is bigger than this size.
Why this issue occurs for SSL sites? The reason is that the request body must be preloaded during the SSL handshake process.
The quickest solution is to increase the upload size limit. IIS uses uploadReadAheadSize parameter in applicationHost.config and web.config files to control this limit.
uploadReadAheadSize Optional uint attribute. Specifies the number of bytes that a Web server will read into a buffer and pass to an ISAPI extension or module. This occurs once per client request. The ISAPI extension or module receives any additional data directly from the client. The value must be between 0 and 2147483647. The default value is 49152.