... About the france.tv issue:
Troubleshooting from outside of France:
1. Geo-block circumvention
As one would expect, this is a media portal site which streams copyrighted audio-visual content, intended for a specific country/region (in this case France); I haven't bothered checking one of their LIVE streams (which are usually the ones most heavily protected against "illegal" access), but chose a VOD URL:
https://www.france.tv/france-2/eurovision-europe-shine-a-light/1468469-emission-du-samedi-16-mai-2020.html
They first check geo-location via
https://player.webservices.francetelevisions.fr/v1/geoloc
where they note the requesting client's timezone, plus they then check actual physical location via
https://geoftv-a.akamaihd.net/ws/edgescape.json
These APIs can't be fooled with an "X-Forwarded-For" request header hack, so to pretend to be in France you'll have to use a whitelisted French HTTPS/SOCKS proxy or a French VPN...
One good source of "open/misconfigured" French proxies suitable for such tests is
http://spys.one/free-proxy-list/FR/
I picked one with small latency and good speed (http://195.154.41.246:5836) and configured New Moon 28 to use it for all connections...
2. Actual testing
I used the latest NM28 offering (package: palemoon-28.9.3a1.win32-git-20200516-a8f7300b9-uxp-9cf4eca9a-xpmod, buildID=20200515224638) with a new, pristine, profile.
I verified the issue reported by @IXOYE with the French proxy in use; thankfully, the screenshot of the NM28 Error Console (btw, the poster was asked to provide Web Console logs, which would've been more verbose, better for troubleshooting) mentions "polyfill.io/v2" and this started ringing some bells...
It turned out the "france.tv player" issue had been already previously reported in the upstream support forum:
https://forum.palemoon.org/viewtopic.php?f=3&t=24269
and the cause is that sites still using the old polyfill.io/v2 library (the current is v3) break in Pale Moon (hence NM), because v2 doesn't detect NM's features well and chokes (more: https://forum.palemoon.org/search.php?keywords=polyfill) ...
The workaround is to use a SSUAO for "cdn.polyfill.io" advertising latest Mozilla Firefox:
general.useragent.override.cdn.polyfill.io;Mozilla/5.0 (Windows NT 6.1; WOW64; rv:75.0) Gecko/20100101 Firefox/75.0
This fixes the issue for me, at least on NM28 and a VOD:
However, be warned that the SSUAO suggested above, while it does fix the france.tv issue, it may break other websites which also use polyfill.io, especially if they have upgraded to its version 3...
FWIW, NM28 is being served by france.tv player MPEG-DASH unencrypted (no DRM) streams, which are also geo-fenced at the manifest/CDN level ; one MPD manifest I managed to sniff is of the template:
https://cloudreplayfrancetv.akamaized.net/7400cc4850ce5/229118575_france-domtom_TA.ism/manifest.mpd?hdnea=exp=1589845397~acl=%2f7400cc4850ce5%2f229118575_france-domtom_TA.ism*~hmac=79fe0976ca3c2982afbf17e1ba2e4d06255857c968f01229a33f37cb5c712cd9
If/when france.tv move to full encryption/DRM, requiring current Widevine support in the browser, then it'd be game-over for XP/Vista users, because latest widevine DLLs require Win7 as a bare minimum...