Help!

I have a 2015 ford fusion 1.5L with a p1450 code (a diagnostic trouble code (DTC) that indicates an issue with a vehicle's fuel tank vacuum system) I also just replaced my oxygen sensor but when I fill up my tank with gas it won’t start for 5-10 minutes takes a few cranks and I don’t know where to start when it comes to replacing parts or to test parts. Any advice?