How to exclude files from backup by extension

I’m a newbie to urbackup. I installed server and client on the same Windows 10 desktop and let it run. In the settings I added some file extensions to be excluded (*.aax; *.iso; *.m4a; *.mov; *.mp4; *.rar; *.tar; *.zip). This way the exclusion does not work.

What did I wrong? Thank you in advance.