Don't worry, we will get your Stryd Paired in no time.
Try plugging in Stryd to ensure that the battery is not dead. See if you see an LED blink or solid LED light. If you see this, Stryd is ok! It just needs to charge.
Ensure that Stryd is not connected to any of your other Bluetooth-enabled devices. Power off all phones and tablets that could be connected to Stryd.
If you would like to start a workout on Zwift, you can only use the Zwift mobile app. Ensure that the Stryd applications (and any others linked to Stryd) is closed on your device. For Zwift to detect you, you need to run at a good tick (~5 mph) and for at least 30 seconds.
If you are having problems pairing Stryd, force quit the Zwift app on all devices and try to record a run with the Stryd app on your phone. If that works, your Stryd is fine and something is wrong with the Zwift app, or the Bluetooth connection between your device and Stryd.
Fifth (Macbook specific):
If you are using a windows computer with ANT dongle, make sure you have all the latest Windows updates installed.