Credentials Invalid using On-premises Data Gateway (Personal) for Pythno Script data

Hello everyone!

I connect data through Python Scripts, and just installed On-premises Data Gateway (Personal Mode) successfully. when I go to PowerBI Server trying to setup Refresh Schedule for the dataset, the Getway Connection shows green status looking good, but in the Data Source Credentials section it shows error

"Your data source can't be refreshed because the credentials are invalid. Please update your credentials and try again."

When I click edit credentials, and click sign in, it shows another error:

" Failed to update data source credentials: ADO.NET: Python installation not found. A Python installation wasn’t found in this location. Please follow the instructions provided in the “How to install Python” link to install Python. If Python is installed and this message persists, provide the installation path in the dialog.Hide details Activity ID: 4347938c-ff3d-4368-950d-50e139cf990d Request ID: 76df8a11-5b65-0950-4fbe-e36864fa0824 Status code: 400 Time: Fri Feb 28 2020 13:12:53 GMT-0800 (Pacific Standard Time) Service version: 13.0.12439.190 Client version: 2002.3.018 Cluster URI: https://wabi-west-us-redirect.analysis.windows.net/