If you receive the error "We are not sure which account is device owner", please solve it by the following method.
One device supports one owner only. So make sure you add the device to just one account.
1. This message comes even your device is brand-new and it’s the first time to add it, Please contact seller for help.
2. If you have added this device with another account before, please log in the other account to delete the device first. Then re-add it with your current account.