@abdulr9515 

Can you try this:

1. Inside your harness, in any section add a button control and give any Test ID (like I have used "ScreenLoadModalButton"). Then add an event as Click and action as Launch Action. Mention the flow action which will be shown as modal popup on the screen. Make Visibility of the button as Never and Reserve space when hidden as checked. Else you can use visibility:hidden; to make it not visible on screen.

2. Create a js file with the following piece of code:

     $(window).load(function () {               document.querySelector('button[data-test-id="ScreenLoadModalButton"]').click();            });

3. Add the js script in Scripts and Styles tab of the harness where you have this section with modal popup.

4. Now launch the portal. On launch itself you should get a modal popup. You can also use Log Off action in the Cancel Button which will make the user logged off from the portal on click of Cancel.

Adding screenprint.