On the Emporia app we use the vehicle's database from Smart Car, a third-party API to integrate vehicle specific information.
If you cannot find the maker of your electrical vehicle to select, don't worry: the only information you won't have by not adding the vehicle to the Emporia app is the state of charge, i.e., the percentage charged on the battery, but you certainly have this info in the car's dashboard / app. Will not affect your EV Chargers' ability to charge w/ all of the functionality already available.
This error happens because some makers do not share the three pieces of information we need to integrate their model of vehicle to our app. We're hoping to provide more options for vehicle integrations moving forwards.