My optical flares is blinking and not working all the timeframe

Your foreground layers act exactly like an object in front of a light would, they block the light, and therefore the lens flare.

If the Station.jpg does not have some effect or mask creating transparency then no light can get through to let the lens flare show up. Does that make sense? Maybe this will help. I start with this night shot with a moon, I duplicate the layer and add calculations, curves and extract to create an alpha channel matte, then I use the Matte layer as a foreground layer so the moon flickers as it goes behind the trees. 

You need some transparency in the layers you use as foreground layers and you need to expect them to block the light when there is no hole in the layer for the light to pass through. 

If purging all memory and disk cache does not fix the problem, this is a good troubleshooting workflow:

Before doing anything else, move down the timeline to where you should be seeing the effect but do not, select the layer that has Optical Flares applied then use the Layer/Open Layer menu to open the layer in the Layer Panel. Make sure Render and Optical Flares are selected at the bottom right of the Layer Panel. If you see the effect then another layer or another effect is blocking the Optical Flares layer. It is time to start troubleshooting the comp.

First, name your layers so you know what is in the comp and where they all are. I can figure out that Optical Flares is applied to the Black Solid in Layer 4 but I have no idea where layers 6 and 7 used as Foreground layers are in the comp or what they contain when the flare is visible at 17:14 in the timeline. I also can't see where Layer 7 - station.jpg is in the first screenshot at 0:00 or what it is supposed to be doing. 

Second, you have every layer soloed in the screenshot. I would select them all and turn off the solo switch for all layers so you can start isolating the problem. 

Third, your timeline does not show the Switches column so I can't see which layers have effects applied. I would use the first and second icons at the bottom left corner of the timeline panel so I could see both the Modes and Switches columns at the same time. 

Now that the timeline and the comp panel are properly set up, move down the timeline until the effect (Optical Flares) appears, then move back one frame so it is gone. Now look for other layers that have effects on them and start turning off the fx in the timeline one layer at a time. If that does not show you where the problem lies turn the fx back on and start turning off layers one at a time until the Optical Flare appears.

If the effect never does reappear, select the Optical Flares layer, press the U key twice to reveal all modified properties in the Optical Flares section of the timeline, and start at the bottom resetting the modified properties. 

If you still can't find the problem then solo the camera and the Optical Flares layer. As long as the layer is in front of the camera you should see the effect.

Let us know what you find. Your screenshots don't give me any clues.