Hi Cedric,
By default, in the EAN barcode, it will accepts only numeric characters, it does not accept any alphabets. EAN-13 encodes 12 digits of numeric data along with a trailing check digit, for a total of 13 digits of barcode data. We have created a sample for the EAN-13 barcode. Please find the sample in below link
If you still face any issues please share us a simple stackblitz sample illustrating issue or modify the above sample replicating issue. This would help us to serve you better.
Regards
Aravind Ravi