Testflight: Could not install App. TestFlight is currently unavailable. Try again.

I have run into this problem today. I distribute a macOS app to internal testflight group from Xcode. Upload to App Store Connect succeeds. I receive the email that a new TestFlight build is available to test in TestFlight. The new build shows in TestFlight app. When I try to install the build I get the following error dialog.

Could not install App. TestFlight is currently unavailable. Try again.

I have submitted feedback FB24059381 with additional information.

I forgot to include that console output during the attempt to install from TestFlight app shows TestFlight for macOS returning HTTP 500.

Testflight: Could not install App. TestFlight is currently unavailable. Try again.
 
 
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