Why can’t I install the latest update for my iPhone XS Max?

I have the automatic installation set up but I still always have to check it and manually update my phone and iPad. That aside, I went to update it and it was done loading but it’s still telling me I need to install the update. I try to click install but it won’t let me (it’s gray-ed out like the option isn’t available anymore). My phone won’t let me make phone calls right now and I’m just trying to update it. Please help!