Why did federal taxes not get taken out of one of my W2s?

Only your employer can answer that.  Did you complete a W-4 tax withholding form for them?

I never wrote down anything in any of the boxes except for check marking c in step 2 because I had two jobs and I believe that is what caused the issue however I do not know

You will need to reach out to your employer to review your W-4 selections.  You can also use TurboTax to update your W-4 form, please see How do I update my 2021 withholdings and print a new W-4? for more information.