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"500 error on combinedresource.ashx" when accessing K2 Management

This article was created in response to a support issue logged with K2. The content may include typographical errors and may be revised at any time without notice. This article is not considered official documentation for K2 software and is provided "as is" with no warranties.


When accessing the K2 Management page, the page does not load correctly and the Browser Console displays a 500 error on CombinedResource.ashx.


In the Windows Event Viewer > K2 Application logs, the following errors are found:

SourceCode.Forms.AppFramework.AsyncException: Asynchronous operation failed ---> System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a send. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host

Troubleshooting Steps

The issue can occur with incorrect TLS version configuration between the Server and Client Protocols.

The TLS Protocol configuration can be verified as per the following K2 KB Article: https://help.k2.com/kb002500
Ensure that Server protocols and Client protocols are configured to match.

Additionally, the following Third-Party application can be used to verify TLS configuration of the Environment: https://www.nartac.com/Products/IISCrypto/