Why does my vivo phone have no signal when making a call, but there is a signal when it can't be reached?

There is no data network during the call, which can be handled as follows:

1. If there is no HD icon in the status bar, please contact the operator to start the VoLTE service or connect to the WiFi network;

2. When using the dual card, you can enter the settings-dual card and mobile network-and open the "Internet access during call/intelligent switching data card". After it is turned on, you can use the data network of the secondary card for a short time when talking;

3. If the location of the 4G/5G network is unstable, it is recommended to try again in another location;

4. When the 5G dual-pass model needs to realize sub-cartoon voice in a part of the 5G frequency band, use the traffic of the main card.

More doubts, hard to carry the phone to the official service center for testing and handling.