You have to first bind your texture. Then render your stuff. Then bind the vanilla icons texture again, because that is what the rest of the HUD code expect. The vanilla hud texture is AbstractGui.ICONS.
Open https://launchermeta.mojang.com/ in your browser and open the HTTPS certificate details. You can usually get them by clicking the lock icon next to the address bar. It should look something like this:
Post the result here, you can use https://imgur.com/ for screenshots.