We switched Portal for ArcGIS security from SAML based identity provider to use Integrated Windows Authentication. After this change I am unable to connect to the Portal using the ArcGIS python API. I can sign into the portal in ArcGIS Pro as well as using the browser. However, I am not able to connect to the portal within ArcGIS Pro Python window. I get the following error message (Attached screenshot) when attempting to connect to the portal using the API.
I have seen a BUG related to this: BUG-000108063
I tested a few python environments in conda and was able to connect to the portal. However, the version of ArcGIS python API has to be 1.2.4 or lower. Unable to connect with a newer version of the API.
Also found a few post talk about this error related to specific version of pywin32 module and recommended using winkerberos. Haven't got success with this approach as well.
This bug fix is implemented today 09/10/2021.