@A_B_SE this error occurs with MS SQL Database. Common reason is that inside the Data Loading activity, for one or more columns of the sample file, the datatype you have selected is not compatible with the data available in actual file.
Carefully review every single column and see if there is a discrepancy.
Additionally this can also happen if for a datetime column the forma from sample file was yyyy/mm/dd and inside the actual file data is present as mm/dd/yyyy or yyyy-mm-dd. If the format is different or if the separator is different you will get this error.