Sometimes the VSA software will become gray in color, either in the short term diamonds in the plugin or in the scanner (see the image). When this happens the first thing to try is shutting down your computer for a few minutes, then starting it back up and checking. If this does not correct the issue, then you will need to reset the activation on your computer.
The following links will take you to the activation reset instructions, choose the trading platform(s) that you have VSA installed on.
Sierra Chart / Infinity AT Charts Activation Reset
NinjaTrader 7 Activation Reset