Resolving validation errors
Resolving validation errors
How to read the checks on a return and what to do about each kind.
Last reviewed 25 October 2026Each return shows a Validation & reconciliation section. If everything passes, it says so and the return is ready for review.
Errors and warnings
- An error holds filing back. The return shows validation failed and cannot be approved until the cause is dealt with.
- A warning is a notice. Review the figures before you approve, but it does not block approval.
Each item shows a plain message and a short code.
Common causes
- A tax template has no decision, or its rows changed. Record a decision. See Record what a tax template means.
- A source exception. An item in your accounts that Onzli could not place. See Source exceptions.
- Accounting scheme or partial exemption. See Accounting scheme and partial exemption.
- A difference from the ledger. A small difference, such as rounding, appears as a warning with the amount.
After you fix the cause
Fixes in ERPNext, or new decisions, do not change a return that has already been calculated. Recalculate the period with New calculation, and the checks run again from scratch.
Related articles
Source exceptions
What to do with an item Onzli could not place in any VAT box.
Record what a tax template means
Tell Onzli once how each ERPNext tax template is treated for VAT.
Preview, approve and submit: the difference
What each stage means, and the point at which anything reaches HMRC.