What is the error, issue?

Can you printscreen the HTTPCaller’s screen?

Using HTTP Caller

Content Type is set to text. Please try and switch that to 

URL Encoded (application/x-www-form-urlencoded)

​@nielsgerrits Thank you for your response.

Still getting this error below

{"message":"","error":{"fields":{"body.emailAddress":{"message":"'emailAddress' is required"},"body.password":{"message":"'password' is required"}},"status":400,"name":"ValidateError","x-request-id":"kcgXSuAoin2FBs4hVrioNOfk48s5crl0s6IIb-SDMZjCsKZXWhBawg=="}}

Ah sorry, because this is a POST, you need to move the parameters from the headers to the body.

In Upload Body you need 

emailAdress=<emailadress>&password=<password>

​@nielsgerrits  Works Perfectly. Thank you for your help