My Mac and my old iPhone 6 used to work with personal hotspot just fine.
I replaced my old iPhone 6 with an iPhone 7 and transferred all my apps and data from the 6 to the 7. Most things worked fine, but not Hotspot.
My Mac remembers my old iPhone 6 and remembers the Hotspot password for that old connection. I think that my Mac thinks the new iPhone 7 is the old iPhone 6 because they have the same name. The Mac shows the Personal Hotspot item in the Wifi menu, where it used to work. When I select the item, the Mac tries to connect using the old password. Now, if I remembered the old password, I could change it on the new iPhone 7 side, but I don't remember the old password.
I can see the password on the iPhone 7, and I want to input that password on the Mac. But I can't find the place on the Mac where I can delete the old password, or change it, or delete the Hotspot item and have it try again from scratch. It just keeps pounding away and telling me "failed to enable Personal Hotspot..."
I tried Personal Hotspot through WiFi. I tried Personal Hotspot through Bluetooth. I tried rebooting.
I just want to find the data on the Mac side and change or delete it (I think if I delete it then the Mac will try again from scratch and prompt me for my password).
EDIT: I found the iPhone entry under the Network -> Advanced -> Wifi gadget and deleted it. Still "failed to enable."