Within the original OpenBSD installation I turned off http/2 within
Firefox but still received the same error.
Firefox's console did not display any errors associated the website.
On the same machine as I was running OpenBSD I installed Ubuntu 20.04 to
a new HD. After booting into Ubuntu I installed an OpenBSD 7.1 virtual
machine (Virtualbox). Firefox within the VM would allow me to login to
the bank websites though 50% of the time it would take two attempts with
the first try resulting in the same error. Firefox w/in Ubuntu itself
would consistently let me login to the bank w/o errors.
I then installed OpenBSD 7.1 onto a WD Passport 1TB drive. On the same
machine I was running my original installation of OpenBSD & now Ubuntu I
booted onto this external drive. I was unable able to login to the bank
as I repeatedly receive the same error as earlier.
I then moved then USB drive to another computer with the same result.
On the second computer I also tried Firefox-ESR but the same error
occurred.
I'll next install OpenBSD 7.0 to the WD drive to see if it works as I
was able to access the bank in the past. If that doesn't work then
something must have changed at the bank and it looks like I'll be forced
to abandon OpenBSD.
I'd like to thank everyone for their time and thoughtful suggestions.
