How to select data sources for Power BI templates

Hi Tangelo-tech 

The reason for the "Data source not supported" error may be that PowerBI cannot directly support custom OAuth 2.0 authentication for off-the-shelf web applications.

You can try the following:

• Instead of relying on OAuth2.0 for each customer in Power BI, you can set up an API gateway that acts as an intermediary between customer data and Power BI. The gateway can use a web application to handle OAuth2.0 authentication and expose simpler authentication methods supported by Power BI, such as API keys. Each customer has a unique API key that is used to grant access to its data. In Power BI, you can use the Web Connector to pull data from the API gateway. 
• In a Power BI template, you can dynamically change the URL or query string of the web connector based on the customer's API key usage parameter. In this way, each customer's instance of a Power BI report can extract the specific data relevant to it. 

Best Regards,
Yulia Xu

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.