Every time computers are running smooth and things are looking fine and you think of looking at the items at the top of your Todo-list, things that you should have done weeks ago but couldn’t because of things preventing you, another one of such blockers kicks in: something does not work.
But IT work can be a bitch as the true error hides behind side effects. In our case here it was the mailserver queuing up messages for no reason. A longer research pointed us to the solution, but those solutions aren’t always what we believe in: “Such a small switch cannot cause problems like that, can it…?”