Finding your way around ZoneAlarm is not very clear. There are tabs down the left hand side - Overview, Firewall, Program control etc. There are also tabs at the top right hand side - for Program control you have a choice of Main and Programs. I suspect you need to go into this Program tab, find your video conferencing program and give it the required permissions. The program will have a green tick, a red cross or a blue question mark. Left click on the symbol and select tick.