Your HMRC filing credentials must be entered in BrightTax before you can submit any returns to HMRC — including Individual Tax Returns, Corporation Tax returns, and Partnership Tax Returns. These credentials authenticate your practice as an authorised HMRC agent.

• You must have administrator permissions in BrightTax to access System Settings.
• You will need your HMRC Agent Services Account credentials — specifically your User ID and password for both Self Assessment and Corporation Tax filing.
• If you do not have an HMRC agent account, register at gov.uk/guidance/get-an-hmrc-agent-services-account before proceeding.

1. Click the cog icon in the top-right corner of BrightTax to open System Settings.
2. Go to Account Information > HMRC Filing Details.
3. Enter your credentials for Self Assessment filing:
   • User ID — your HMRC agent User ID for Self Assessment.
   • Password — your corresponding HMRC password.
4. Enter your credentials for Corporation Tax filing:
   • User ID — your HMRC agent User ID for Corporation Tax.
   • Password — your corresponding HMRC password.
5. Click Save.

The best way to confirm your credentials are working correctly is to attempt a test submission or run a check-and-calculate on a return. If your credentials are incorrect, HMRC will return an authentication error at the point of submission.

Common HMRC error codes related to credentials:

• 1001 / 1002 — invalid User ID or password. Check your credentials and re-enter.
• 1003 — account locked. You may have entered incorrect credentials too many times. Reset your password via HMRC's agent portal.

I am getting an authentication error when submitting

• Double-check that the credentials entered in BrightTax exactly match those used to log in to the HMRC agent portal.
• Ensure you are using agent credentials, not personal HMRC login details.
• If you have recently changed your HMRC password, update BrightTax with the new password.

I do not know my HMRC agent credentials

• Log in to the HMRC agent portal at gov.uk to retrieve or reset your credentials.
• If you are setting up as a new agent, you will need to register for an HMRC Agent Services Account before you can file.

Q: Do I need separate credentials for Self Assessment and Corporation Tax?

A: Yes. HMRC issues separate User IDs for Self Assessment and Corporation Tax filing. Both must be entered in BrightTax.

Q: What credentials are used for Partnership Tax Return submissions?

A: Partnership Tax Returns are filed using the Corporation Tax credentials entered in BrightTax.

Q: How often do I need to update my HMRC credentials in BrightTax?

A: Only when your HMRC password changes. If you update your password in the HMRC portal, update it in BrightTax at the same time to avoid submission failures.