P0455, EVAP System Leak Detected?

I was driving the other day and my DIC Showed to check the gas cap, and I did, the thing was fine and tight, now idk what is happening. It did it again the other day, where could I be having a leak come from? It finally threw a cell code for it, otherwise it would just say on the DIC "Check Gas Cap". Could it be the seal around the gas cap?

 

bumpppp

 

you're EVAP line o.O

 

Vent Valve Solenoid is going to be replaced hopefully this week... that is what the problem is...