Google Apps Script: DoubleClickCampaigns.UserProfiles.list() "Failed with error = null"

[Marco Schierhorn]

Hi Google Apps Script Support Forum,

I'm currently trying to get the API working in Google Apps Script.

But when I execute the following code:

function listUserProfiles() {

// Retrieve the list of available user profiles

try {

const profiles = DoubleClickCampaigns.UserProfiles.list();

if (profiles.items) {

// Print out the user ID and name of each

for (let i = 0; i < profiles.items.length; i++) {

const profile = profiles.items[i];

Logger.log('Found profile with ID %s and name "%s".',

profile.profileId, profile.userName);

}

}

} catch (e) {

// TODO (Developer) - Handle exception

Logger.log('Failed with error: %s', e.error);

}

}

I always get this error "Failed with error: null". It's hard to debug it, as it seems that the API Call directly fails. I have also activated the CM360 API in the Google project.
And another questions is, can I also use a service account with the Google Apps Script Service "DoubleClickCampaigns"? 

Thanks,
Marco