The quality of the video streaming depends on your Internet bandwidth as well as Wi-Fi signal strength. It is normally an indication of low bandwidth or weak Wi-Fi signal when live streaming is intermittent. Try moving Snap closer to the router if Wi-Fi is an issue.
If bandwidth is not an issue, and the Snap was previously working without problems, usually power cycling the Snap will resolve the matter.
Generally, many gaps in the replay timeline indicate that the Snap may not have adequate Wi-Fi signal strength and/or bandwidth.