App starts on Win10 PC, but blank screen when picking channel

After moving my Quad tuner Tablo to a friend’s house because his antenna reception was better and he has fiber internet, I am trying to remote-watch it from my place, with mixed results. On py iPhone, works great. On my PC though, the Win10 app comes up, and I can click various meny items, like settings, recordings etc. I can even watch recordings but when I click left channel name on the tv guide, video doesn’t start. I get a Play button (right-pointing triangle on the left , a 0:/0: indicator, CC, back 20, vol, and full screen but no video. Is it because my PC is not "authorized to remote view? If I press the Play triangle, nothing. What’s (not) going on?