I am having trouble casting videos from my pc to my chromecast on my television. Sometimes when I click the "cast" button it says "Cast this tab to ...Beta. Sometimes it says cast (and then there is a long stream of letters) to..beta. If the long stream of letters is listed it will cast. If it simply says cast this tab to...beta then it will not cast. It keeps telling me to select a chromecast. Why is this issue occurring?