What does error code E07 mean on the Trail 2 e-bike, and how do I fix it?

E07 means the bike isn't communicating with the battery, usually because of wet or dirty battery contacts. Remove the battery, dry and clean both sides of the contacts, reinsert it until it clicks, lock it, and turn the bike on. If the error returns, fully charge the battery and try again. If it still shows up, a warranty claim is the next step.