NFE-888

Rejeição: GTIN da unidade tributável (cEANTrib) sem informação [nItem: …] (use "SEM GTIN").

In English cEANTrib is empty; a product without a GTIN takes "SEM GTIN" (MEI issuers, CRT 4, excepted).

error: the document is invalid

What the rule checks

As the rule set's publisher wrote it. The rule runs on every element the context matches, and fails where the test is false; the validator reports the line of that element.