No signal - HDMI

Hi, I'm using yodeck since 2 days and have a problem with it. It loses signal and shows 'No signal' after a while - sometimes it works perfectly for few hours, but sometimes it happens every 15 minutes. Rebooting device helps but it's not a solution. Monitor is all the time visible as 'online' in yodeck app (with up-to-date 'last seen online' and screenshot time) EDIT - TV doesn't support HDMI CEC.