Below are some common HMRC CIS (Construction Industry Scheme) error codes and how to resolve them.

Error 3001

Description
HMRC have rejected the CIS submission because some subcontractor details are invalid or missing.

Typical causes

• Incorrect UTR (Unique Taxpayer Reference)
• Missing or invalid National Insurance number
• Subcontractor name does not match HMRC’s records
• The subcontractor has not been verified with HMRC

How to resolve

1. Check the subcontractor’s UTR and ensure it has been entered correctly.
2. Confirm the name and other personal details exactly match HMRC’s records.
3. Make sure the National Insurance number (if required) is entered and is valid.
4. Confirm that the subcontractor has been verified with HMRC before including them in the return.
5. Update the details in your software and resubmit the CIS return.

Error 7912

Description
HMRC are indicating that the CIS information has already been reported (possible duplicate submission).

Typical causes

• A return has already been successfully submitted for this tax month/period
• The same subcontractor and payment combination has already been sent
• The software has resubmitted the same data (e.g. after a timeout or connection issue)

How to resolve

1. Check your HMRC online account or submission history to confirm whether the return for that period has already been accepted.
2. If you need to correct figures that have already been submitted, send another return that includes all subcontractors again. HMRC will use this new return and completely override the previous one.

Important - Is the error caused by an HMRC outage?
If your CIS300 fails or hangs during a period when submissions were previously working, the issue may be with HMRC's servers rather than your data. Before making changes to subcontractor details, check the HMRC service availability page at https://www.gov.uk/government/collections/hm-revenue-customs-service-availability-and-issues.