Usually there are some common points that might influence the reliability of the Godox strobes:

1. Distance - the sender has two menu options here. One setting for distant strobes and one for very close strobes. Many users report unreliable shots when using close distance to strobes when not applying the 0-n meter setting. On the Xpro trigger, e.g. go to menu -> Scroll down to dist -> set 0-30m.
2. Battery level - although the sender seems to run fine on rechargeable batteries, some users reported unreliable function with half empty batteries or rechargeables.
3. Interference - this can be either other devices using the same band like WIFI hotspots, which then can be helped by trying out other channels - or in some cases structural obstacles either hidden in the walls or visible.
4. Using it too fast - the obvious thing, but sometimes even that might happen. If you are not sure, if that is the case, enable the recharge beep on the device to hear if you can take another shot.
5. Flash bothered by itself - I had one photo session, where the flash switched back to full power from time to time. This ended after taking out the batteries and restarting the flash.