A method is provided that restricts execution of a job where a finished sheet which is specified in a job, and another finished sheet that is fed, do not match each other. The method for controlling a data processing apparatus for causing a post-processing apparatus to execute post-processing on a print product output by executing printing based on print data received from an information processing apparatus includes inputting image data generated by reading a sheet to be post-processed, receiving checking data for checking an image of the sheet, and restricting, if the checking data does not match the input image data, execution of the post-processing.