Signup using a existing email address provides a undefined error

[StephenOTT]

Like a error to be resolved with Authentication and Identities MS
@mario-digitalstate

morgan@site.com already existed, and the error was expected, but the message is incorrect.

[baddlan]

Error details are missing in the response from {{authentication}}{{environment}}/registration

{
  "type": "https://tools.ietf.org/html/rfc2616#section-10",
  "title": "An error occurred",
  "detail": "",
  "violations": []
}