Upload attendance. Error No file attached

I got the error as following, have anyone faced this problem?

Traceback (most recent call last):
File “/home/ubuntu/frappe-bench/apps/frappe/frappe/handler.py”, line 118, in uploadfile
ret = method()
File “/home/ubuntu/frappe-bench/apps/erpnext/erpnext/hr/doctype/upload_attendance/upload_attendance.py”, line 100, in upload
rows = read_csv_content_from_uploaded_file()
File “/home/ubuntu/frappe-bench/apps/frappe/frappe/utils/csvutils.py”, line 19, in read_csv_content_from_uploaded_file
return read_csv_content(fcontent, ignore_encoding)
File “/home/ubuntu/frappe-bench/apps/frappe/frappe/utils/csvutils.py”, line 45, in read_csv_content
fcontent = text_type(fcontent, encoding)
TypeError: coercing to Unicode: need string or buffer, NoneType found

hi, same issue when import XLS.