Job is not sent to AME queue from extendscript file

Hi,

I have created a CEP extension for Premier Pro, and i'm trying to use app.encoder object to create a new proxy from the project item (app.encoder.encodeProjectItem...). This method is returning the job id and Adobe Media Encoder is opened, but the job is not sent to the queue... 

The code is:

const presetPath = 'path_to_preset/preset.epr';
const outputPath = '/output.mp4';
const projectItem = app.project.rootItem.children[0];
const workArea = 1;
const removeUponCompletion = 1;
const jobID = app.encoder.encodeProjectItem(projectItem, outputPath, presetPath, workArea, removeUponCompletion);
app.encoder.startBatch();
return jobID && outputPath; 

Note: Weird thing here is that it works if i start the debug mode in vscode (ExtendScript Debugger extension).

is there something missing to get it working properly?

Thanks in advance,

Rubén.