There must be exactly 6 numbers for each entry in column R.
To ensure any preceding zeros are recognised, you will need to adjust the number format for the cells in column R.
To do this you will need to right click the column header (R) and select Format Cells from the menu. Then select CUSTOM and add 6 0s into the TYPE field, as per the screenshot below:
📌Note: If you reopen the file and make any changes before uploading to DDCMS, you will need to apply the above format to the cells again before saving and uploading.