HMRC Submission: Error 1046 - Authentication Failure

Article ID: 2025205           Last updated: 17 November 2015


Depending on your company file you may receive more than one error message when trying to submit your returns. Most messages received from the HMRC validation gateway will likely indicate to you where the problem lay.

It is important to note any errors that appear on your screen in detail; preferably take a screen image if you need to contact the Mamut Support Team. 


Error 1046

Error: 1046   Type: Fatal   Message: Authentication Failure

The supplied user credentials failed validation for the requested service

The HMRC gateway checks and cross-checks 4 pieces of information in order to authenticate and allow a submission.

1.  Your gateway User ID

2.  Your gateway Password

3.  Your company's Tax Office Number

4.  Your company's Tax Office Reference



  1. Check you have correctly entered your HMRC gateway User ID and Password.  Ensure that there are no spaces before or after the characters you entered into any of these information fields. For example [Smith ], or [ Smith].  
  2. As a double-check, try going to the HMRC website and login with the same User ID and Password.  If this works, then you know that they are correct.
  3. In AccountEdge, go to Setup> Payroll Information an ensure that the Tax Office Number and Tax Office Reference are correct.
  • The Tax Office Number is usually 3 or 4 digits. For example 123.
  • The Tax Office Reference is usually a letter and 3 numbers, or sometimes two letters and 3 or 4 numbers. For example, A777 or AB345

Note!  HMRC usually provides the Tax Office Number and Reference as one string, separated with a slash, for example 123/A777 or 123/AB345.



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