Cel code P0442

My 575 cel came on last year, conveniently before my annual service. My Indy smoke tested and replaced the evap valve. A few months later it triggered a cel again, and my code reader read P0442, small leak in the evap system. I don’t know if it was same code as before, since I didn’t check the 1st one.

id rather not send the car for service for just this issue. What’s the likelihood it’s a loose gas cap seal? If high I might just buy a replacement to try it first

thanks for any input!