IBM Netezza error Certificate Chain Not Trusted

Although we have successfully used an ODBC connection in Power BI to connect to our IBM Netezza, we would prefer to use the the built-in IBM Netezza connector. However, we have had no success with it. We enter the server name, the database name, click Next, enter the user account and password. Clicking OK then gives us the dialog "Truststore error: Certificate Chain error".

We have reviewed and attempted various suggestions in this forum, including unchecking the Encrypt box in the Global Permissions. In fact, when we change Global Permissions and then try to create a new connection via Get Data, Power BI does not use the existing permissions but creates a new Global Permissions entry (see screen capture below).

Are Global Permissions supposed to be "picked up" and used by the Data Sources dialog? If we are missing a step or process somewhere, please share.

Also saw this thread, but the Netezza dialog in Power BI does not allow users to switch the type of credential.

https://community.powerbi.com/t5/Power-Query/Certificate-Chain-Not-Trusted-Error-Effecting-PowerBI-Only/m-p/361730#M15791

Any other thoughts what the blocker might be?

Thank you!