Operation Manual

The smartphone's contact list hasn't been synchronized with your
smartwatch. After establishing a Bluetooth connection between the
two devices, you need to synchronize the contact list.
5.6 Poor phone call quality
The distance between the smartwatch and the smartphone is too
far. The Bluetooth signal is too weak. Please reduce the distance
between the devices. The mobile signal in a given place is too weak.
Please try to make a call in a place with stronger signal.