Redmine

The API generally expects correctly encoded data depending on the format in which you send the data:

• text/xml or application/xml - You can specify the encoding in the XML document if required. The default is UTF-8.
• application/json - JSON documents MUST always be UTF-8 encoded
• application/x-www-form-urlencoded - We generally expect UTF-8 encoded data here.

Aha that's good to know. But the issue is more about the API not giving any information about this isn't very clear when reading the error code.