Unable to select items in the Combo Box

Hi Team,
I am unable to select the items in the Combo Box.
Able to click inside the combo box.
But the select items are not displayed in the combo box.
Attached the screenshot

Here I want to select the CC Usage.
Able to find the Xpath and click the CC Usage
But the cursor moved inside the CC usage.
steps done manually:
1 when I click the nearby dropdown button ,The mouse cursor moves inside the CC usage Text box .
2.But able to click again the Dropdown button and the list items are displayed.
When I automate, during first click the focus goes inside the CC usage Text box and not able to click again and no list items are displayed
Pls help.
Pls let me know if u want more details

Maybe this is not going to be easy since that HTML is not valid.

There is no such thing as an input element with type=combo in HTML.

There is an Aria-role type, combobox, but that is not what you are dealing with.

Your first action should be to inform the web page developers that they are producing invalid HTML. This is likely to cause problems when trying to run validation tests. This could hamper automation testing, too.

That said…

What happens to the DOM when you click on the dropdown? Can you capture a screenshot showing the changes?