This can occur for a variety of reasons such as a server, system or ISP being overwhelmed, or your home network dropping momentarily. If this happens, try to reconnect.

Some things to look out for on your home network:

1) Are you too far from your wifi router? Make sure the signal is strong. If not, consider moving closer to the wifi router. Also, consider plugging directly into your router with a network cable if that is at all possible. A wired network is more stable than a wireless one.

2) Is anybody else in your house streaming (such as YouTube, Netflix, etc.)? If so, might have to ask them to stop. Depending on your home network, steaming an HD movie, for example, can overwhelm a slower home internet connection.

It is possible that your home Internet connection can be experiencing problems, especially if many people in the area / neighborhood / city are using it heavily. This may not be noticeable when browsing the web, or streaming video/audio in a one-way download; however it will be noticeable when doing live two-way video or audio. You may want to contact your ISP to ask if loads are high in your area. You can also try power cycling your cable modem and wireless router. If a video+audio call is choppy, try turning off video and see if audio improves.