Below are the market hours for Forex (US/Eastern).
The highest volume / most activity is found during the periods where the markets overlap (seen below). For this reason, these periods are generally considered the best times to trade.
If you have run Investor/RT without closing it through the weekend when Daylight Saving Time (DST) changes took place in the US, it is recommended that you exit Investor/RT and start up again.
Periodically, market data servers send Investor/RT a time of day notification to ensure that the user's computer clock is in sync with the server. When the time of day sent by the server, which we consider authoritative, is offset more than a second or two from the current time of day on your computer clock, this message will appear. It indicates a condition that should be corrected. It is important that your computer clock be set to the exact hour/minute/second every day.