[Enhancement] Better error message for `not_authorised`

[thorwebdev]

I was going mad because I kept getting the

{"message":"Error","type":"not_authorised","reason":"Not Authorized"}

error. Until I realised that I was missing the ?type=rt in my JWT creation call 🙈

[nickgerig]

Thanks for the request @thorwebdev we'll feed that back. Glad you got it working