Hi @shankar431 ,
I believe the Skype for Business 2015 management pack is not supported by SCOM 2019, although it doesn’t mean it won’t work, it has simply not been tested/verified by Microsoft.
There is a Skype for Business 2019 management pack, you’ll find it over here:
https://www.microsoft.com/en-us/download/details.aspx?id=57511
Here’s some more documentation on how to monitor Skype for Business 2019 with SCOM:
https://learn.microsoft.com/en-us/skypeforbusiness/tools/scom-management-pack-use-2019
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Best regards,
Leon