The UniFi Access Ponit (AP) default SSH password is as follows. It may vary depending on the model of the device.
UniFi Devices – ubnt / ubnt
UniFi Devices – root / ubnt
If the UniFi AP is a device defined on the UniFi Controller, the SSH account information of the UniFi AP is located on the panel. In the UniFi Controller panel we can access the account information under Advanced in the System menu.