When you submit your CIS Return, you can receive a submission error. Use this guide to understand each message and how to fix it.

Error: 1046 Authentication Error

HMRC doesn't recognise the details when submitting a CIS Return.

To troubleshoot:

• Confirm Credentials are correct by logging into the Government Gateway. If CIS doesn't show there, contact HMRC
• Enter the Employer's PAYE Reference and Accounts Office Reference correctly. Go to Construction Industry Scheme within Financial settings
• Ensure you enter the correct User ID and Password during submission. You'll enter this after selecting Submit to HMRC
• Check your HMRC account to see if you're registered to submit online
• If you're submitting on behalf of a client, ensure you’re registered as their Agent with HMRC
• If the issue persists, contact HMRC

Error: 3001 or 5012

If you receive a 3001 or 5012 error message, this means that the Supplier details aren't Valid.

You'll need to look at the contact details of your CIS supplier. Make sure the contact's name and their CIS registration number are correct.

For steps on how to edit a CIS contact read the following articles:

• Set up a contact as a contractor for CIS
• Set up a contact as a subcontractor for CIS