I am able to connect to OracleDB from Power BI desktop. after publishing the dashboard and having the on premises gateway setup, it was working fine. I installed on premises gateway on another system to keep that running full time. the gateway is personal mode, that's why. I uninstalled the latter and now have it only on the first system. this is also personal mode and had worked fine until I installed the gateway on another system.

Regardless of how many times I publish the dashboard, I'm not able to set up auto refresh with the same credentials of the OracleDB

I keep getting:

Failed to update data source credentials: An error happened while reading data from the provider: 'Object reference not set to an instance of an object.'