Checked the web application on my side by executing and debugging for the impact of the incorrect format of date for the period covered and see why the data inserted is not a date. As per checking, the web application gets the data as number(44013) and not the correct value of the field from the excel, checked the previously uploaded file as per user, the previously uploaded file uploaded the correct date, as per checking, there are some fields with no value, thus will request for the previously uploaded and compare it to the current file.