LL5.6 Updates Quit Working

[Planorez]

I have a problem installing updates.  I get an error message with an instruction to go to the Forum for help.  Here  is the data shown in my error window. 

===========================
Install Updates Error log
===========================
Install Updates could not fetch the package cache information lists.
Go to https://dfgkh547-jsdfv8.iyhkj.tk/forums/ and paste the log below into a new or existing thread for assistance.

============ Log ===========

Hit:1 http://repo.linuxliteos.com/linuxlite emerald InRelease
Hit:2 http://security.ubuntu.com/ubuntu focal-security InRelease
Hit:3 http://apt.keepsolid.com/ubuntu focal InRelease
Hit:4 http://us.archive.ubuntu.com/ubuntu focal InRelease
Hit:5 https://dl.google.com/linux/chrome/deb stable InRelease
Hit:6 http://us.archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:7 http://archive.canonical.com/ubuntu focal InRelease
Hit:8 http://us.archive.ubuntu.com/ubuntu focal-backports InRelease
Get:9 https://packages.microsoft.com/repos/edge stable InRelease [7,343 B]
Err:9 https://packages.microsoft.com/repos/edge stable InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY EB3E94ADBE1229CF
Reading package lists...
W: GPG error: https://packages.microsoft.com/repos/edge stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY EB3E94ADBE1229CF
E: The repository 'https://packages.microsoft.com/repos/edge stable InRelease' is not signed.

Thanks for your help.