I added the Chrome repo following instructions on this site https://www.linuxbabe.com/desktop-li...suse-leap-42-1

I know it says leap 42.1, but it should work for Leap 15.1 right? It did for leap 15.
It is after the
zypper ref
instruction that the error first occurs.
The repo is added to the YaST list.

Then subsequently in YaST, the following error messages popup.

I get this error
File repomd.xml from repository Google-Chrome
is signed with the following GnuPG key, but the integrity check failed: 

ID: 7721F63BD38B4796
Fingerprint: EB4C 1BFD 4F04 2F6D DDCC EC91 7721 F63B D38B 4796
Name: Google Inc. (Linux Packages Signing Authority) <linux-packages-keymaster@google.com>
Created: 04/12/2016
Expires: Never

The file has been changed, either by accident or by an attacker,
since the repository creator signed it. Using it is a big risk
for the integrity and security of your system.

Use it anyway?
Right or wrong, I answered Yes to that question.

And this
Cannot access installation media 
 (Medium 1).
Check whether the server is accessible.