HMRC's message · HTTP 400
The specified tax year is not supported. The tax year specified is before the minimum tax year value
When it appears
Any income tax request that names a tax year.
What to check
- The tax year the software is working in for this client.
- Whether the work belongs on an ordinary Self Assessment return.
How to fix it
Move to a supported tax year. Earlier years go on a Self Assessment return.
Making Tax Digital in Accountin
Accountin will send VAT returns and income tax updates to HMRC once HMRC grants it live access. It then shows HMRC's code and message next to a plain explanation, and keeps HMRC's reply against every submission.