A family of Microsoft word processing software products for creating web, email, and print documents.
Not working manually!
If it isn't working for you, then something is preventing you from saving your template.
If you are on a network, for example work or school/university, a login script may be deleting or replacing your Normal template each time you sign in.
A simple test is to locate the Normal template in the user templates folder, if you are running Word on a PC, and check the time stamp. There should be a modification date when you add your keyboard shortcut (and also when you make other intentional changes that affect the template), but there should be no unexpected date & time stamps.