Imported excel file showing black screen

I upload an excel file in both CSV and Xlsx format to see if either worked to the ‘assets’ folder in online version. However, after uploading the file nothing shows up. I see that the file is attached but when clicking on it nothing appears. I implimented a readExcelFile and such to the code and shows no errors but still nothing happens when saved and published. Please help, running out of time on this thanks