Relation, authorisation and sequence errorsRelation & missing element

CDS12003Uniqueness Error: Reuse of LRN (D.E. 2/5) is not allowed within 48 hours

HMRC explanation

Local reference number duplication
You used the same local reference number (LRN) within 48 hours. Change the LRN or add a version number at the end using letters and numbers only.

Source: HMRC, Customs Declaration Service error codes, Open Government Licence v3.0. GOV.UK publication · Licence

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