I have my manager account with some campaigns on it. When I run GetCampaigns.php example from GitHub it shows Number of results found: 0. As I found out MCC acoount's campaigns are "invisible" for API. The thing is that I have a task to show campaigns with its data exactly from this MCC account. Is there a way I can solve my problem?
Even though you can see campaigns for a manager account in the Google Ads web interface, these actually belong to the sub-accounts of the MCC. Managed accounts themselves don't have campaigns.
What you'll probably want to do is to get the list of managed accounts using the ManagedCustomerService and then iterate over the returned account IDs, running GetCampaigns.php for each of them.