Request filtering is configured on the Web server to deny the request because the content length exceeds the configured value.
What you can try:
Verify the configuration/system.webServer/security/requestFiltering/requestLimits@maxAllowedContentLength setting in the applicationhost.config or web.config file.
More Information... This is a security feature. Do not change this feature unless the scope of the change is fully understood. You can configure the IIS 7.0 server to reject requests whose content length is greater than a specified value. If the request's content length is greater than the configured length, this error is returned. If the content length requires an increase, modify the configuration/system.webServer/security/requestFiltering/requestLimits@maxAllowedContentLength setting.
Rather than turning off request filtering in IIS7 entirely, it's better to keep it on but increase the maxAllowedContentLength .
Go to c:\windows\system32\inetsrv\config\applicationHost.config and change <section name="requestFiltering" overrideModeDefault="Deny" /> to <section name="requestFiltering" overrideModeDefault="Allow" />
then add to your application's web.config: <system.webServer> <security> <requestFiltering> <requestLimits maxAllowedContentLength ="2147482624" /> <!-- value in bytes : this is just less than 2GB--> </requestFiltering> </security> <system.webServer>