Unfortunately the username/password you use to DoubleClick through the web browser will not work. Instead you have to set-up a new username/password to allow API access. This is something that Google insist upon, so unfortunately it's out of our hands. Your DoubleClick representative or system administrator will be able to do this for you.
That's right. Matt, you need to reach out to your Google/DoubleClick TAM (Technical Account Manager) to both enable your instance of DFA for API access (via Omniscope's connector, or any other product for that matter). Your TAM may/may not issue a new set of credentials to log in.
James Sandoval SVP & Managing Director, EMEA BrightTag