got error on customer create

[winnie80]

Description
Got error 500 on using /api/v1/customers/create , method POST
This is the result

{
    "status": false,
    "message": "An unexpected error occurred. Please try again later."
}

At this point I'm not sure what did I do wrong.
I tried to trace back inside api-bundle but could not even find proper customers.yaml within routes

How to reproduce
Use route /api/v1/customers/create.
Use method POST
Send as JSON the following parameters : firstName, lastName, email, contactNumber and isActive (boolean)
For example

{
    "firstName": "first",
    "lastName": "last",
    "email": "user1@email.com",
    "contactNumber": "",
    "isActive": true
}

Thanks