Common TSS Errors and What Causes Them

"I can't find my TSS number"

This question comes up constantly, mostly because "TSS number" means three different things depending on context:

• Your EORI number, issued by HMRC, identifies your business to customs.
• Your UKIMS authorisation number, if you hold one, arrives in your UKIMS approval letter.
• The TSS reference attached to a specific declaration or movement record, found in the portal next to that record. If you can't locate a reference, start with the record itself in the portal before contacting support.

Read the Full context on Northern Ireland customs guide for better understanding.

Declaration queries from vague goods descriptions

Goods descriptions need to be specific enough for customs to identify what's in the consignment. "Clothes" triggers a query. "Men's cotton knitted shirts, size XL" doesn't. This is one of the most common, and most avoidable, causes of delay.

Missing Goods Movement Reference at the port

For roll-on roll-off traffic, GVMS bundles declaration references into a single Goods Movement Reference before the vehicle can travel. Inside TSS, the GMR is built from declaration data already supplied, which is exactly why incomplete declarations at step 6 of the movement workflow cause problems at the port.

UKIMS eligibility rejections

UKIMS requires a clean customs and tax compliance record over three years, documented internal controls tracking goods from arrival to end use, and five years of accessible supporting evidence. Missing any of these at application stage is the most common rejection cause.

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