Tax return submission errors

Tax return submission errors

Tax return submission errors


What is this?

If your hmrc credentials are wrong, you will see:

Authentication Failure. The supplied user credentials failed validation for the requested service. 

You should be able to fix this quickly by yourself:

Double-check your Government Gateway password (and ID). For example, try logging into your HMRC Online Account and resetting your password if necessary.


If it’s your first time doing your own tax return, check your HMRC Online Account. You should see a box called Self Assessment.

If not, follow the instructions at the top of the page to Add a tax to your account.


If you’ve already submitted a tax return for the year, you may see:

A submission for the user and tax year has already been successfully made. If amendment(s) are required, you must make an amended submission.    

You can resolve this within ApariPro by selecting the resubmission option at the end of the tax return.


If you are unsure what the error means or relates to, please submit a help ticket with our support team here 


If you need any assistance please check out the other articles in our Help Centre for how to get started using your account and if you have any further questions you can contact our support team here
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