So far except for navigating to another screen, I cannot think of another way to make it disappear automantically. After you navigate to another screen, this message will disappeat after a short while. Also, you can manually close this window by selecting the "X" on the right side:
Since this window does not show as a control in PowerApps, you cannot make it unvisible using a timer control.
Community Support Team _ Mona Li If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.