Solutions:
1. Most of the echoes are caused by network problems. It is suggested to change the network environment and make a call in another place.
Note: Network environment problems do not specifically refer to weak cell phone signals, and call echo is generally independent of cell phone signal strength.
2. Backup, restore factory Settings, and try to call before the backup is not restored.
3. Update to the latest version of the system.
4. If the above solutions fail to work, it may be caused by hardware problems, and it is suggested to go to after-sales center for inspection.