"Connection Failed. Try Again" AirPods error.......

Hi. so I just ordered my AirPods 5 months ago. But today, when I upgraded my iPhone 7 to iOS 12.2, AirPods just doesn't connect anymore. When the pop-up window appears, saying that it is to connect, it's connecting. But then, the following error appears: "Connection Failed. Try Again". Even though Bluetooth is on and the AirPods in the case are close to the iPhone, the error still comes up. They have become virtually unusable.

Why can't I connect my AirPods anymore? Is there any solution to this problem?