Xiaomi 4 WeChat can receive information normally, but there is no prompt tone. What is the reason?

Set the items of [I]-> [Settings]-> [New Message Reminder] in Xiaomi's mobile phone, such as [Accept new message notification], [Receive voice and video chat invitation notification], [Video chat, voice chat ringtone] and [Sound] to ON.

The specific steps are as follows:

1. Click [I] on the mobile phone WeChat interface to open the following interface, and then click [Settings];

2. In the setting interface, click New Message Reminder, as shown in the figure below;

3. The items such as [accept new message notification], [receive voice and video chat invitation notification], [video chat, voice chat ringtone] and [sound] are set to ON, as shown in the following figure.