One of the two typical failures on a Lync 2013/SfB 2015 Environment are to have more than one server with Power Settings with the standard configuration. Yes I know… I thought exactly the same that you are thinking right now, but yes, I had the same mistake.
This kind of errors are easy to resolve and it has not impact in the platform (Myself apply it on a production platform with no issues).
All Lync/SfB Servers must have a high performance powerplan. Usually servers have selected “balanced”, recommended for windows, but in isn’t a best practices for Sfb.
To apply the best practices for Skype for Business/Lync 2013 you must select “high performance”. Sometimes, you can’t select this option, but don’t worry, it isn’t the end.
If you can’t select in first instance, you can unlock the option after click on “Change settings that are currently unavailable” and then the options will be unlocked.
You only need select the correct checkbox and close the windows to apply it.
I hope this information will be useful for you