Can you add some more details here about what content key policies you are using? Clearly you are using DRM or AES-128 encryption along with the Azure Media Player.
DRM systems change by OS and Browser.
You may want to review this article on dynamic encryption - https://learn.microsoft.com/en-us/azure/media-services/latest/content-protection-overview
Also check the compatibility matrix table here for all the DRM tech combinations available across OS and Browser combinations - https://learn.microsoft.com/en-us/azure/media-services/azure-media-player/azure-media-player-playback-technology
UPDATE: Based on your comments here and on StackOverflow - you may have been testing PlayReady on Edge for Mac OS?
Edge on Windows 10 support both Playready and Widevine Edge on Mac supports Widevine only (I believe... checking for a definitive link to that support...)
Safari on Mac of course is FairPlay only.
You can test some DRM combinations using the AMP demo page here. Don't forget you need to use HTTPS!
Edge on Mac does not support PlayReady.
Did you mean Edge on Mac?
Edge on Mac OS only supports Widevine DRM I believe. No PlayReady.