Do you have any other apple products connected via Bluetooth whilst using your AirPods, like an Apple Watch? If so, try disconnecting from that first then try your AirPods. After thinking I had bought a dud pair of AirPods I started googling and came across people suggesting that other Apple products being connected at the same time was interfering with other BT connections. I disconnected my watch, paired my AirPods and they worked fine. Turned my watch back on, still all good. This also fixed the BT connection in my car (have to disconnect watch from my phone first). Hopefully this is resolved in the next software update as it’s quite annoying.