addSubscriber error

[ir-fuel]

I try adding a subscriber to a list:

    const api = new createsend(auth)

    const details = {
      EmailAddress: 'joris@test.com',
      Name: 'Joris Joris'
    }
    api.subscribers.addSubscriber('some-list-id', details, (err) => {
      if (err) {

Result:

[Error: Unable to parse JSON.  Error: Error: Can't render headers after they are sent to the client.
Body:
"joris@test.com"]

Any idea what's going on?

[drj-io]

@ir-fuel Check to make sure your api key is correct

[nufyoot]

@ir-fuel I'm getting back into this project now. Are you still having issues?

[ir-fuel]

I don't even remember in which project I was using this. Since it didn't work I started using something else.