Back to having Add To Playlist errors

[cucklescuckles]

Plan: Free

Country: USA

Device: Desktop via Chromium 77.0.3832.0 / Opera 63.0.3353.0 / IE 11.0.9600.19377

Operating System: Windows 7 x64

My Question or Issue:

Early this morning, Spotify reset its sign-in cookie, and thereafter has given me nothing but trouble. Also, I've looked at the traffic and am absolutely sure that no malware or MITMing or anything else hinky was or is occurring. Primarily, the Add to Playlist button (from any playing song, however navigated-to) fails out every time, like a few weeks ago but this time at least redirecting to an error-page. Also playback is frequently interrupted (but not in such a pattern I can catch it repeatably) and overall, interaction with the site in general is noticeably slower.