Check in BC that the mapping between your setup BC and PEPPOL codes matches the list of units of measure on the below link
This is how it's done from Danish GREEN to PEPPOL RED
The error will occur if the setup is incorrect
{"message":"Invalid Document","errors":[{"context":"/Invoice[1]/InvoiceLine[1]/InvoicedQuantity[1]","pattern":"","text":"[BR-CL-23] [BR-CL-23]-Unit code MUST be coded according to the UN/ECE Recommendation 20 with\n Rec 21 extension","isWarning":false},{"context":"/Invoice[1]/InvoiceLine[1]/Price[1]/BaseQuantity[1]","pattern":"","text":"[BR-CL-23] [BR-CL-23]-Unit code MUST be coded according to the UN/ECE Recommendation 20 with\n Rec 21 extension","isWarning":false}]}'
The official PEPPOL unit of measure list can be found below
Peppol BIS Billing 3.0 | Rules
The Most Common Approved Unit Codes in PEPPOL BIS Billing V3
!!! On the first linie you have Nothing C62, you use for like comment linies, and the always safe to use is EA
| UN/CEFACT (unit code) | Meaning |
| C62 | no unit |
| EA | each |
| 28 | kg/m² |
| 2N | dB |
| 4H | µm |
| 4K | mA |
| 4P | N/m |
| A24 | cd/m² |
| A86 | GHz |
| A94 | g/mol |
| B22 | kA |
| B32 | kg • m2 |
| B43 | kJ/(kg.K) |
| B49 | kΩ |
| B61 | lm/W |
| BAR | bar |
| BX | Box / Box |
| C16 | mm/s |
| C24 | mPa.s |
| C26 | ms |
| C45 | nm |
| C65 | Pa.s |
| C91 | 1/K |
| C94 | min-1 |
| CDL | cd |
| CEL | °C |
| CMQ | cm³ |
| CMT | cm |
| D33 | T |
| D52 | W/K |
| D74 | kg/mol |
| DAY | d |
| DD | ° |
| E01 | N/cm² |
| E32 | l/h |
| FAR | F |
| GM | g/m² |
| GRM | g |
| HTZ | Hz |
| HUR | h |
| KEL | K |
| KGM | kg |
| KGS | kg/s |
| KHZ | kHz |
| KL | kg/m |
| KMQ | kg/m³ |
| KVT | kV |
| KWT | kW |
| L2 | l/min |
| LTR | l |
| LUM | lm |
| LUX | lx |
| MBR | mbar |
| MHZ | MHz |
| MIN | min |
| MMK | mm² |
| MMQ | mm³ |
| MMT | mm |
| MPA | MPa |
| MQH | m3/h |
| MQS | m³/s |
| MTK | m² |
| MTQ | m³ |
| MTR | m |
| MTS | m/s |
| NEW | N |
| NU | N • m |
| NU | N.m |
| OHM | Ω |
| P1 | % |
| PAL | Pa |
| SEC | s |
| VLT | V |
| WTT | W |
