Please try Microsoft Remote Desktop Version 10.6.3 that is just released on Apr 20, 2021.
In this release we fixed a bug that was causing the client to return a 0x507 error code.
In addition, we enabled the following features on Apple Silicon:
• Support for the AVC420 codec.
• Smart card redirection (requires macOS 11.2 or later).
Thanks to everyone who reported bugs and worked with us to diagnose and fix issues. If you encounter any errors, you can contact us via Help > Report an Issue.
Best Regards
Karlie
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