I have Skype for Business on Windows 7. For a long time I've always been able to click these "Join Skype Meeting" links in e-mails and calendar appointments from co-workers.
Starting last week these quit working for me. No changes have been made to my Skype or Outlook/Office. It keeps directing me to some Microsoft/Skype webpage that wants me to download the meetings plugin. I already had that, but I tried re-installing it several times to no avail.
I can still join meetings if someone directly adds me or if I click the button in "Join Lync Meeting" button in Outlook (which is weird because neither I nor anyone else is still using Lync... we upgraded to Skype for Business a year ago). The "Join Online Meeting" button also does not work.