There is an additional sheet in the bulk upload file: If there are multiple files or sheets, then the transaction will fail.
No special characters are allowed in the amount column.
The second row is kept empty: The second row after the heading there must be some value. If the row is kept empty the file will not get processed.
The file format is wrong: The key is to stick to the format provided in the dashboard which is either .xlsx or .csv.
The details provided are wrong or the details are missing.