How to resolve the error message, “Unable to determine the data source due to unknown functions...”

Hello v-yangliu-msft, 

Thank you for the response! I brought up your suggested solution and the referenced documents in a recent team meeting.

Regarding your suggestion to update the data source credentials, that does not apply to our project because the Python code we used to connect Power BI desktop to Redcap has no credentials. Additionally, the issue that was addressed in the first document involves custom connectors and making sure that the proper files are in the right folder to be detected by the gateway. As mentioned in the post, we did not use custom connectors in our connection process. Lastly, the final document described the exact same error code as us. The solution suggested was to make sure that all installed Python packages are currently supported by Power BI. When I checked the list, the PyCap package was not present.

Just to make sure that this might be the reason why we are experiencing issues in scheduling a refresh, was the PyCap package supported last year?