Yes, your JSON object is invalid meaning it’s not structured properly. This error is not specific to Velo and is just about JSON objects in general so you may google if you want to learn more, but here is an example of JSON object structure.
Alternatively, if you are unable to get your object structured properly, you can set the variables in your function instead of the test data area are variables and just remove them when you are done testing
{"roleID":"the-role-id-value", "email":"test@email.com"}