Most declaration errors show up in the same handful of fields. Here is how to spot them fast.
EORI mismatches
An XI EORI is often needed for Northern Ireland movements, alongside or instead of a GB EORI. If TSS or CDS rejects your declaration on the party identifier, check which EORI is registered against the trader profile.
Commodity code issues
Codes must be current and correctly structured. An outdated code will pass a quick eyeball test but fail validation in TSS or CDS.
The Northern Ireland trader guidance is useful when you are triaging whether the issue is with the movement type or the reference data.
Procedure code errors
Wrong procedure code combinations are one of the most frequent CDS rejections. If your TSS submission fails, procedure codes are the second thing to check after EORI.
Valuation and currency
Missing incoterms, currency mismatches or invoice value mismatches are common causes of holds. Fix them at data source, not at the portal.
CDS access delays
CDS access usually arrives within two hours, but can take up to five working days if HMRC needs extra checks. If you have just registered, that is expected, not broken.
Amendment loops
If you keep amending the same field, the problem is upstream data, not the portal. Fix the source, not the last mile.
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