Headlight bulb not working
 

I planned to upgrade my lights to HID. So I just ordered recently from https://www.xenonpro.com/ and then installed it in my car. The problem is when I finished installing, only one is working but I installed the both bulbs exactly the same.

HID Issue
 

Some HID ballasts aren't wired correctly - bench test it with jumpers and see if it matches your light socket's polarity.
I ditched my HIDs for CSP chip LEDs. Instant on, super bright, and longer life.
My ballasts and/or bulbs typically failed within a year, and color matching the bulbs, even though they were labelled the same color temperature, was a real pain.

Do a search on Aliexpress.com for CSP LED. Look for the bulbs with 12 CSP chips each. COBs aren't as bright, but cheaper.
If you can't wait for shipping from China, pay extra and get them on ebay.