This is a stand alone install of Sage CRM 2018 R3 on a Windows 10 computer. I'm running Sage CRM with demo data so that I can figure out how it works. The browser makes no difference, tried Chrome, Edge, IE.
When I go to Administration > System > System Behavior > Change I get a message that pops up with:
Sign in
http://computer-name
Your connection to this site is not private
Username
Password
Clearly I missed something during the install or setup.