Who I have the same questioned this topic

That's all I know.  Tethering Error.

I check the Portable WiFi hotspot box, get the "checking subscription status" overlay, get the "Turning WiFi on" message, some message flashes by to quickly to read (I think it shows my SSID), then "Error".

I was using Portable WiFi Hotspot tethering from around 8pm to 9:30pm when it suddenly stopped working.  Under "Portable WiFi hotspot", it said "Error" with no other explanation.  I powered-cycled the phone with no change.  I shut down, pulled the battery for a few minutes, restarted with no change.  I did a SIM pull (first for 15 seconds as tier 1 support suggested, then for 5 minutes as tier 2 suggested) with no change.  The tier 2 person said she was going to check the switch while I was powered down for the 5 minute period, then call me but I haven't received the callback approximately 30 minutes later.  Also tried USB tethering with the same result.

I can still access the internet just fine on the phone but tethering seems broken.  Has anyone else seen this behavior from their phone?  The Verizon rep assures me that there is no block on my account (I've moved about 7 gigs via 3G on my unlimited account this billing cycle) and that there are no known problems in my area.  I didn't make any changes to my setup before this happened and I've been using tethering on this phone for months.  Years on my previous phone.