Signature verification for Repo skype-stable failed

Am am still at the bottom of the class. I followed all the instructions from Microsoft Skype for Linux installation including adding the gpg key but I am still getting the captioned error. I did get Skype working so I have no idea what is wrong or why even with failed signature Skype works. Where am I going wrong please?

All OK now. I hadn’t updated the key using sudo zypper dup. That did what was necessary and now OK. Sorry to be so dumb.