Jul 20, 2026 · HMRC advise that the best way of resolving this 403 error is by following this guide. If you are receiving the 403 (Forbidden) TAX_PERIOD_NOT_ENDED, this is because during the fetch for …

HMRC customers (and their agents) will use digital record-keeping software to interact directly with our systems via the MTD APIs. The sandbox endpoint is...

Apr 16, 2026 · Hit an HMRC MTD error code mid-submission? Here's what each code actually means, why it happens, and exactly how to fix it without calling HMRC.

Sep 30, 2025 · To resolve this, follow the steps in our 'Error code: TAX_PERIOD_NOT_ENDED' article. You’ll see this error if you submit your first MTD VAT Return without activating MTD in Sage 50 …

Nov 3, 2025 · This error prevents VAT data from being submitted or retrieved through MTD. It usually means the HMRC registration or authorisation process has not been fully completed.

We cannot access HMRC systems to check what is wrong within your digital account and the clients MTD VAT registration. The following below error messages might occur when you are connecting to …

MTDfVAT Product Support. Here you can find Making Tax Digital for VAT Advice, answers to the most frequently asked MTDfVAT questions, and Support Documentation.