Adding a note here as I couldn't find the answer anywhere Googling and a lot of trial & error to solve but your post came up quite high when searching, so I'll add it here unless anyone thinks it worthy of a bug report & fix post somewhere:
If you use https links with the "$Link" tag in "LessonsEN.txt" it doesn't work and you get "Failed to resolve the link to" error messages when clicking.
Basically https doesn't work and isn't recognised as a link, only http (without the s) does.
Something Ableton ought to fix given the importance of https to web url security - but now you know if you had the same issue and trouble finding out why.
It seems that most templates or files I found online had a mix of the https links included that don't work either, so it's a common use-case but until solved by Ableton the workaround is changing https to http.
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