I also experienced this issue. I fixed it by updating the browser.
Here's what happened:
First time attempt to log-in to Wells Fargo after Opera installed on my new PC. I had been using Opera on my old PC for a few weeks, so I am pretty that this was not an issue with Opera previously.
I used Aria to check for issues, which is how I found this forum thread. I checked cookies, cache, and site security settings with no luck.
Wells Fargo official browser compatibility is limited to Edge, Chrome, Safari and Firefox.
My version of Opera 118.0.5461.60
Updated to 118.0.5461.83. Fixed! Security updates were listed as part of the update, which I guess is most updates, but presumably that's what made the difference.