Can't get text from popup on website

Hi all, i using katalon studio, i have a problem when I can’t get text from popup on website, the result returns ’ ’ even though the interface is displayed.
WebUI.getText(findTestObject(‘Page_OnOnPay - Thanh toan thong minh/div_Ten_khach_hang’), FailureHandling.STOP_ON_FAILURE)

Text of object ‘Object Repository/Page_OnOnPay - Thanh toan thong minh/div_Ten_khach_hang’ is: ‘’

See this:

The more information you give, it will be easier to troubleshoot.