Software problem
New applications or system updates may affect video calling. If you download a new application and suddenly find that video calling can't be used, you can try to update the application, restart the phone, or check the settings of the application to see if there is any wrong operation.
Hardware problem
Video calls can also be affected by camera, microphone or speaker failures. If your camera goes on strike, or the voice of the call is intermittent, you have to check whether these hardware are normal. Remember to repair or replace it in time if necessary!
network problems
Video calls need stable network support. If you are in a place where the WiFi signal is weak or the mobile data signal is poor, the video call may be intermittent. At this time, you can try to switch to a more stable network, or consider increasing the bandwidth to make video calls smoother.
Other possibilities
Besides software, hardware and network problems, there are some other possibilities, such as server failure. In this case, you can only wait patiently for the service provider to solve the problem.