You are unable to access K2 application components such as K2 Designer, K2 Workspace or K2 Management. This issue occurs due to the use of HTTP/2 in newer browsers, which has stricter requirements than HTTP/1.1. For more on HTTP/2, you can read the following Microsoft documentation:


You will see the following errors:

This often occurs with the use of Windows 2016.

Troubleshooting Steps

Although not a K2 issue, the errors caused by use of HTTP/2 can prevent usability of K2 components. Thus, this can be a crucial thing to check when coming across these types of errors.

This issue is primarily caused by incorrect ordering of blacklisted cipher suites. To re-order the cipher suites, you can download the IIS Crypto 2.0 tool here:

Once downloaded, you can refer to the following Microsoft documentation for steps on how to reorder blacklisted cipher suites to the bottom of your list:

You can find a complete list of blacklisted ciphers here: