Why is the timer switch I installed causing the light it is connected to to flicker?

I just installed a programmable timer switch to the gang panel housing the switch for my porch light. The wire colors provided are black, blue, and green. I connected the wires correctly (black to black, blue to red, and green to ground. I programmed the light correctly, but now the light flickers and gives off a... show more I just installed a programmable timer switch to the gang panel housing the switch for my porch light. The wire colors provided are black, blue, and green. I connected the wires correctly (black to black, blue to red, and green to ground. I programmed the light correctly, but now the light flickers and gives off a humming sound. What did I do wrong? There are no loose connections.
Update: It is a CFL bulb. 120v 60hz.
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