Keyword set shortcuts appear not to work

When I m holding down the Alt-key numbers appear as they should underneath the keywords in my set. However,  no keywords are assigned to the photos chosen when I then press the numbers on my keyboard. Thus, I have to use the mouse instead.

  Any ideas why? Is this a specific keyboard thing? 

 I’m running the newest version of windows 10 and and Lightroom 

best regards from Lars 🙏