When creating shipping labels, the following error occurs:

Shipping labels could not be created: SOAP-ERROR: Encoding: string ... is not a valid utf-8 string


The API user or password contain invalid characters.


The API user and/or password must be changed so they do NOT contain the following characters:

  • umlauts (ä, ö, ü)
  • ampersand (&)
  • German Eszett (ß)
  • characters with diacritical marks (for example é, ê, í)

Also note this article about the login configuration.