Relation, authorisation and sequence errorsRelation & missing element
CDS12141Relation Error: Incompatible goods movements declared. AI codes 'NIDOM' and 'NIIMP' must not be entered together on the same declaration.
HMRC explanation
What to check across the Relation, authorisation and sequence errors
Two elements, or a value and a rule, disagree. Read both elements together: completing one element with a particular code often requires another value, and the fault is frequently in the element you did not change. The family also covers parties and authorisations that are not recognised, references that must be unique, and messages sent out of sequence.
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Source: HMRC, Customs Declaration Service error codes, Open Government Licence v3.0. GOV.UK publication · Licence