Switch off auto throttle, down the throttle, and maximize the throttle again and switch on your auto trottle again. It worked with me. The warning sign is a false alarm if your pressure is set on auto. Also try to select a lower cruising Altitude when climbing and when you reached your cruising Altitude, maximize it. Hope I helped you: marnusmatthysen@gmail.com
Sorry actually ment on my previous post: Select lower cruising speed while you climb. Appologies