BR-CL-14
A rule of the European standard EN 16931 – applies to every invoice following the standard, including Peppol BIS Billing 3.0.
What this error means
BR-CL-14
The country code is not a valid two-letter ISO 3166-1 code (e.g. a typo or lowercase letters).
How to fix it
Use two capital letters: LT, PL, LV, DE, SE… (not "Lt", not "GER").