This barcode has no data. You get a blank space where the scan target should be.
Supply the field data.
^XA^BY3^FO50,50^BCN,100,Y,N,N^FD^FS^XZ
A barcode field with an empty ^FD, or no ^FD at all before ^FS.
Neither ^PW nor ^LL is set. Both fall back to a value stored in the individual printer, not to a value in the spec — so the same ZPL prints differently on two printers of the same model.
Set ^PW and ^LL explicitly in every format.
The bar width is outside the GS1-128 range (0.495 mm to 0.940 mm, 0.495 mm target). At 203 dpi that means ^BY 4 or greater.
Raise ^BY to at least 4 at 203 dpi, or 6 at 300 dpi.
At 203 dpi ^BY2 — the power-up default — and ^BY3 both fail GS1.
This GS1-128 is shorter than the 31.75 mm GS1 requires. It may scan on a handheld and fail at a fixed scanner.
Set the height to at least 254 dots at 203 dpi, or 375 at 300 dpi.
This barcode has no data. You get a blank space where the scan target should be.
Supply the field data.