Appreciate if someone can help. I change both my camshaft sensors and now I am getting a P0021 code. I also changed the oil and made sure the level was good. can someone please help

Ensure the sensors' harnesses are free of debris and corrosion, maybe try some electrical contact cleaner. Also ensure the torque is correct for the bolt securing the sensors (the spec is 85 inch-pounds). It looks like there is an O-ring installed with the sensor that must be replaced if removed (see EM-100, item #16). Did you replace it? Both sensors appear to have this O-ring. I'm not sure whether the sensors come with them or if they're already pre-installed on the sensor.

Thanks for teh reply. I had a mechanic replace the two cam shaft sensor becuase I had earlier engine code. And they charged like $300. After all the things I have learnt, I could have done that myself. And I want to give a try fixing the p0021 code myself first before I take it back to the mechanic. I can ask them about the o ring. but I will check the torque today.
When you talk about the harness, are you referring to the wires and plug that plug into the sensor?

Yes, that is correct regarding the harness.

if that "mechanic" just changed the part without testing the circuit & the same code came back, bring it back to him to honor the warranty!

I hope you asked for the old parts back, so you can test the old parts to see if they were good to begin with

most people think after pulling the trouble codes, it's usually the part's fault; that's not the case...

you need to test the circuit as well as testing the vacuum lines, grounds, etc...