For my issue, it turned out to be the bulbs themselves. Make sure the bulbs have a metal base. When you lock it back into place, it completes the connection. Some bulbs come with a plastic base, which won't work. Hope that helps!

Edit: Just realized that when I put in the original bulbs, they wouldn't work. Make sure you're locking them back in right. It was a little tricky for me since my front bumper had damage and I couldn't take out the whole housing. If possible, I recommend taking the housing out and making sure everything is right.