The link to the forumpost in those mails are to https://forum01.team-mediaportal.com/threads/etc, and that site doesn't seem to have a valid certificate. (Firefox is complaining that the connection is not secure).
Don't remember when I clicked on those links lately so unfortunately I can't give a timeframe on when this issue arose.
Don't remember when I clicked on those links lately so unfortunately I can't give a timeframe on when this issue arose.