They were expecting to show the men's match, so live tennis will be back on after Serena's match. But they have 2 women's matches scheduled after that in which they should show both Vee and Serena's matches.
Tennis Channel has the rights to the night session. Serena vs Jie is still part of the day session and is probably being shown on your local FSN station. Live tennis coverage will begin as soon as the current match is over.