error codes

Hi guys, today I bought a 2021 carrera vengeance e bike, it has error 00 and 21 I knew it had a error 21 and thought that there was no speed sensor on it, I turned the bike over and it was below the crank, I then repositioned it to the correct place and put some wd40 in the connections, then I...

Hi guys. Im shattered. I got a conversion kit of aliexpress. Good seller 98% good reviews. And battery from wing bikes. But it doesn't work. After hooking everything up motor doesn't start, when pedalling. Throttle doesn't work, it seems like it's going to start and wheel moves half inch and...