Had a code PO442, replaced gas cap, now I've progressed to PO455

Question

2004 Silverado CEL light on and code PO442 came up. Bought a new AC cap and now I get CEL and message to tighten cap and it gives a code PO455.

Answer 1

P0442 Evaporative emission control system (small leak)
P0455 Evaporative emission control system (Large leak)
You may just have to reuse the old fuel cap if the and clear the code, if the code comes back as small leak . the fuel cap is the problem