When you have a form that fails authorization, this passes Azure auth but when logging in using ADFS this fails internally, however externally this works as expected. In the environment ADFS is set up to work directly with K2 rather than via Azure.
You will see the following error:
"Failed to sign in, could not authenticate
Username or password incorrect
This appears to be a configuration issue. The best way to help troubleshoot this issue is to have a look at the K2 API web.config. This can be located within the following directory:
Program Files (x86) >>> K2 Blackpearl >>> Webservices >>> K2 Api >>> Web.config
Please double check if the settings in regards to the article below have been applied to the web.config, particularly steps 26-31 that are mainly to do with the web.config.