You've got the provider for the actual charger (a handful of different providers), which needs to negotiate with the car via CCS. This can fail in umpteen different ways, as car manufacturers differ on how they implement CCS (Dunno how, but it happens).

Then you've got the software in the charging point, which needs to be customised for the brand you're selling under (another moving part).

And lastly, you have the back end system for the brand, which handles authentication, authorization (RFID or App) and billing - this is the bit that ultimately gives the charger the go-ahead to start feeding power to the connected car.

Any of these fails, no electricity for you.

For 22kW "slow" chargers this is a bit simpler as the actual charger is a lot less complex, it doesn't need to negotiate, it just needs to switch one relay.

Tesla is like Apple in this case, they take care of the whole stack. So as long as the charger has power, it'll work. Authentication and authorization are done by having the car negotiate with the charger directly via the charging cable, no dongles or apps needed.