The field Document Number must match the regular expression '^([a-zA-Z1-9]{1}= [a-zA-Z0-9/-]{0,15})$'

Error
1

It seems like the document number is not matching according to the E-invoice portal regular expression.

We request you to please change the invoice serial number according to the below instructions.

  1. Must start with a letter or a digit between 1-9.
  2. Can contain up to 15 more characters (letters, numbers, hyphens, or slashes).
  3. Total length of invoice serial number is 1 minimum and 16 maximum characters.
  4. Cannot start with 0 or special characters like - or /.