Error is showing while adding the ODBC Dataset to gateway for scheduled refresh.

Hi , hb0135 

The error code "Unable to connect to the data source. Either the data source is inaccessible, a connection timeout occurred, or the data source credentials are invalid" seems that the we use this credential can not connect to the data source.

First, you can use Power BI Desktop to test whether you can use ODBC to connect to the data source on the computer where you installed the local data gateway. Note that we need the computer where the local data gateway is installed to have permission to access our data source.

At the same time, you can also try to uninstall and install the latest version of the gateway to rule out the problem of the gateway version.

Power BI Gateway | Microsoft Power BI

Secondly,You can also check if the user has the necessary permissions to access the data source and if the firewall is not blocking the connection. 

The authentication types available are:

• Default or Custom: Select this authentication type when you don't specify any credentials if you're using DSN configured with a username and password. Or, if you need to include credentials as connection string properties.
• Windows: Select this authentication type if you want to connect using Windows authentication. Optionally, include any connection string properties you need.
• Database: Select this authentication type to use a username and password to access a data source with an ODBC driver. Optionally, include any connection string properties you need. This is the default selection.

For this you can refer to :
Power Query ODBC connector - Power Query | Microsoft Learn

And also you can check the ODBC connection string ,for this you can refer to :
Power BI gateway and Report Builder support for ODBC data sources - Power BI | Microsoft Learn

Thank you for your time and sharing, and thank you for your support and understanding of PowerBI! 

Best Regards,

Aniya Zhang

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