Cause
The content has invalid Unicode characters, for example lone surrogates or a long run of combining marks.
What to do
Send valid UTF-8 text.
application/problem+json
{
"type": "https://masnet.com/developers/errors/invalid_unicode",
"title": "Invalid Unicode",
"status": 422,
"detail": "...",
"code": "invalid_unicode",
"correlation_id": "..."
}