Not sure what you are meaning, but there are different kinds of barcode encodings, (Code-39, Code-128, Code-11, and a shitload of other encodings), and depending on the scanner used by the client, it might not support the one you chosen to encode you barcode with.
You can analyse the generated barcode here https://online-barcode-reader.inliteresearch.com/
And you can create barcodes here https://barcode.tec-it.com/en