I did nothing different. I assume all the changes were on the FT/IB side of things.

I'll be back in Chicago Monday afternoon and will report back to make sure it still works there.

Update:

When I returned home on the afternoon of Monday 20 February, I found that connecting to FT while using NordVPN in the Chicago area no longer works.

I find this very interesting. It seems like I was able to connect to FT for a couple of weeks (starting on/near 8 February). The last successful connection was on Thursday 16 February. When I arrived in the St Louis area on the afternoon of Thursday 16 February, I could not connect to FT using NordVPN. On my return to the Chicago area last Monday (20 February) it did not work.

Update #2:

I had not tried accessing FT with my VPN active for 3 or 4 days and this morning it now works.