CredentialMissing for SQL kind inside Custom Connector

Tyr Modify your as follow, pass both the server and databas

let 
    result = ms_test_ext.Contents("myserver-ondemand.sql.azuresynapse.net", "mydatabase")
in 
    result

 
Not much of an indea since your one is a custom connector, asuming this is done using power m query, I can suggest following as well, 

•  Ensure the DataSourcePath matches what the SQL source (myserver-ondemand.sql.azuresynapse.net) expects. This includes both the server name and the database name.

• The CredentialMissing error often happens when the SQL credentials are not propagated correctly from the custom connector.

• You're passing only the server URL, but SQL often requires both server and database names explicitly. Adjust the connector to expect both parameters.

  Additional Steps

  - Clear existing credentials from Data Source Settings in Power BI.

On 2nd thought, Looking at the code snippet in your screenshot, the issue might be related to how credentials are handled in your custom connector. Below are the adjustments and steps to ensure credentials are correctly passed and recognized by your custom data source (ms_test_ext).

Updated Code for ms_test_ext.pq

Add an Authentication property in the DataSource.Kind configuration to specify UsernamePassword authentication. This tells Power BI how to handle credentials for your custom connector.

[DataSource.Kind = "ms_test_ext", Publish = "ms_test_ext.Publish"]
shared ms_test_ext.Contents = (url as text) =>
    let
        Source = Sql.Databases(url),
        db = Source{[Name = "db"]}[Data]
    in
        db;

ms_test_ext = [
    Authentication = [
        UsernamePassword = []
    ],
    Label = "Custom SQL Data Source"
];
​

Explanation of Changes

1. Authentication Property:

   • The Authentication property is added to explicitly support UsernamePassword. Without this, Power BI may fail to recognize or prompt for the credentials.

   • Simplified Parameter Handling:

     • The optional keyword was removed from the url parameter for simplicity.

     • Label Property:

       • A descriptive label is added for clarity when selecting the connector in Power BI.

         ---

         Additional Steps

         1. Set Credentials in Power BI Desktop

         After implementing the updated code:

         • Import the connector (ms_test_ext).
         • When prompted, enter the SQL server username and password.

           2. Test in Power Query SDK

           Before deploying the connector, test it using the Power Query SDK to ensure it correctly requests and uses the credentials.

           3. Validate Data Source Settings

           Ensure no conflicting or cached credentials exist:

           • Navigate to File > Options and Settings > Data Source Settings in Power BI Desktop.
           • Locate and clear any existing settings for ms_test_ext.
           • Re-enter credentials.

             4. Verify Deployment Environment

             If deploying to Power BI Service:

             • Ensure the custom connector is signed.
             • Configure the Power BI Gateway to use the appropriate authentication method.

               ---

               If you still encounter issues, provide the detailed error logs or let me know, and I can assist further!

What's the reason for bolting this onto a standard SQL connection?