If you attempt to start a rental and come across a generic error message check that the station has had a few minutes when first turned on to upload and download information with the network.
All Brick stations globally connect with the network every five minutes, during what we call a 'heartbeat'. If a station is turned on and a user immediately initiates a rental, they will likely encounter an error. Turn the station, let it sit for a five minute digital heartbeat. If you are still running into issues, check the troubleshooting guide.