Error code 5012 - The usual cause for this error message will be a missing UTR or National Insurance number in a subcontractor's record. Other causes inlcude incorrect/invalid characters or formatting of the subcontractor's name/details. Use a hyphen instead of a space where there are double middle names.

If this error is due to there being a subcontractor with no UTR, ensure that the unmatched status has been applied for that subcontractor. A UTR is not a manadatory value, but where you do not have the UTR you must set the status as unmatched.

Re-open the subcontractor's payment for the period you are submitting the CIS 300 return. Enter the UTR or change the Tax Payment Status to 'Unmatched (30%)'. Save the change.

Back on the Payments screen, ensure that the rate on the right side of the screen says 'Unmatched':

Re-finalise the subcontractor's payment and try to submit the CIS300 once more.