[TrailMixRaisin]

At least in some android phones the term factory reset is misleading. If you "only" factory reset, you will need to have access to the original Google account to use the phone afterwards. If you want to sell your phone you need to first disconnect it from your account and then factory reset it.

This is done to prevent selling of stolen phones but due to the bad naming it can be a hassle for legitimate sellers. The website seems not to mention this. At least in the phones I checked.