What steps can be taken to reactivate AT&T Hotspot on my iPhone?

No one here on this user to user only forum, nor even at Apple can help you. Hotspot is a carrier provided feature. You'll have to work with your carrier to resolve whatever the issue is. If AT&T is your carrier, that means contact them for help.

Carrier settings updates come directly from the carrier, not Apple. I’m not saying a data compromise is your issue, but I’m sure a lot of engineers are temporarily working on other issues.

The carrier writes a lot of the firmware and software for the mobile settings, modem etc. Your best source of information will be your carrier’s support team.

You need to work with ATT on this as they manage the hotspot function.

Mine started doing the same thing right after I "updated carrier settings". No hotspot, after an hour on the phone with AT&T going over everything I tried for the last few days I get, "Oh it looks like it is a trending issue, IT people are working on it, was there anything else I can help with?" Apple tech support was very quick and tested the phone before I called AT&T. So yea, now it's a trending issue.

My hotspot stopped working in the last 2 weeks. My wife’s phone on the same account also doesn’t work. A device will connect but has no internet access. Calling into AT&T they told me they were aware of a bug and were working on a fix.

I also have the same problem starting mid-July. Spent 1/2 hr in chat with a very helpful Apple rep who did ALL the checks on my system. It's fine.

Now on the phone waiting for AT&T to reply - their callback does not work (doesn't recognize the # 1) so I have to listen to them play music and tell me to use the web for estimated 45 minutes.

Shoutout to Apple Support for being responsive. AT&T is not earning similar brownie points.

As you likely already know, AT&T recently experienced a massive system wide data breach. It's going to take some time to sort things out.

I am also having this issue. Have not gotten to the bottom of it with AT&T’s live chat tech support.

The support tech did say it’s supposed to be fixed in the next 48 hours. Given how long it’s been going on, I’ll take that with a grain of salt, but wanted to pass that info on.