I have the same problem. My battery failed for no apparent reason, I managed to get it working again by checking the cells, I had a bare cable, I fixed this, the battery turns on, but not the bike.
I contacted the seller, Vitus Bike US directly and they have closed their operations. I have no warranty, no response.
I contacted the seller, Vitus Bike US directly and they have closed their operations. I have no warranty, no response.