Chrome: AdBlock, turning it off does not fix the problem.
Firefox: AdBlock Plus, turning it off also does not resolve the issue.
No specific security software, aside from anything Ubuntu has by default (where I have not changed any settings, with Evernote Web working before Tuesday).
Chrome: on "Standard protection", cookies are allowed although a "Do not track" request is sent to browsing traffic. I added evernote.com to cookie whitelist (including third-party), but it did not help.
Firefox: I did use custom tracking protection here (including blocking cookies), but turning it off (to Standard level) does not fix the problem.
No, I do not use anything specific.
Yes, I have tested Chrome Version 91.0.4472.101 (Official Build) (64-bit) and Firefox 89.0 (64-bit), on Ubuntu 20.04.2 LTS.