Login error w/ Postman but not *Rested*

testing api/login endpoint. credentials work fine using the Rested tool but using same headers and parameters throws a 401 unauthorized error?

In Rested - Parameters:
Accept application/json
Content-Type application/json
email email@email.com
password mypassword

Rested response includes a content-length of 81 whereas the Postman response with the same parameters generates… content-length of 38??? Not sure if that matters… and the response body = error: true, reason: unauthorized

Anyone know why login works with the less sophisticated tool called Rested and not Postman using the same parameters?

thx.