Error: This Layout is not a Draft, please checkout. Even tough it is in draft mode

Hello,

whenever I am trying to change the backgroundcolor of my layout I get the following error

{ error: 
   { message: 'This Layout is not a Draft, please checkout.',
     code: 422,
     data: { property: 'layoutId' } } }

The layout is in draft status (at least that whats the web GUI tells me).
My api call looks like this:

request.put({url: baseUrl + ‘/background/’ + layoutId, auth: {bearer: this.token}, formData: {backgroundColor: backgroundColor, backgroundzIndex: 0}}, function (err, httpRes, body) {
if(err) {
callback(err);
} else {
const jsonBody = JSON.parse(body);
callback(null, jsonBody);
}
baseUrl is http://domainNameToXibo/api/layout
I could not find the solution, so I hope someone here can help me.