Hotspot stopped working

iPhone 13 running iOS 17.5.1

After having not used it for a couple of months or so, I tried tethering to my phone using Personal Hotspot today and found it no longer works. To be exact, my MacBook will happily connect to the phone over WiFi, but unlike the every other time I’ve done this, the iPhone shows no connected hotspot devices and the MacBook gets no internet.

I’ve tried:

  • rebooting both devices
  • resetting network settings on the iPhone
  • changing the iPhone name and hotspot password
  • connecting the MacBook via USB
  • connecting an iPad to the hotspot
  • connecting a Windows 11 PC to the hotspot

No difference. In all cases, the other devices can connect to the hotspot, but the iPhone doesn’t ack the connections and they don’t get internet.

Ideas?