A problem with FTP and the connection to my server.
I recently reinstalled UEStudio, an editor I have not used for a while, since I used Sublime most of the time. But that’s a different story.
UEStudio has the ability to connect directly to FTP and edit files online. However, the connection was stuck at “Retrieving directory listing …” after connection. It worked without encryption with plain FTP, but that’s not really an option these days.
So I looked through the settings and found a setting for passive transfer. I remembered that this setting was needed to be set in the past, but I did not have to do that in any other client in the last years. Or maybe this is set automatically in other clients.
After that it was working again.