Could not connect to server

I am a new user totheproduct - I purchased and installed it today - set it up using my gmail account, downloaded the software for my Windoes 7 machine, ran all, completed setup - connected fine - disconnected - no I can no longer connect - could not connect to server - I checked the icon on my PC and I am logged in - I have the corrct setting on the Ipad and I am signed in. Any help will be appreciated