Hello @Cleavon
As I found from here , Version 10.5.1 support macOS 10.13 or later, so the version compatibility shouldn't be a problem.
Have you tried to download and install beta version?
https://install.appcenter.ms/orgs/rdmacios-k2vy/apps/microsoft-remote-desktop-for-mac/distribution_groups/all-users-of-microsoft-remote-desktop-for-mac
The test version is newer than the official version published on app store, and it will collect users' problems and try to fix them before publishing official version.
You will probably get more help by going here : https://discussions.apple.com/welcome
Best Regards
Karlie
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