JavaScript Promise – Uncaught (in promise)

I’m learning about JavaScript’s Promise function and I expect to run the following in sequence:

• Do_System_Refresh(); –> In this function, I call the AJAX function within System_Refresh() for some purposes.
• Do_Refresh_UI();

I tried the following, but I encountered an exception: Uncaught (in promise) Error: A listener indicated an asynchronous response by returning true, but the message channel closed before a response was received.

async function Do_System_Refresh()
{
 let p = new Promise(function(Do_Refresh) {
     Do_Refresh_UI();
 });

 await System_Refresh();
}

async function System_Refresh()
{
   call ajax here
}

function Do_Refresh_UI()
{
   alert('here do refresh called');
} 

What did I do wrong?

I need advice, many thanks in advance.