I cannot create PPS data source(DS) at sub-site level.
For example : when I am creating DS at site : https://mysp.a.b then everything works.
When I am trying to create DS at subsite : https://mysp.a.b/mysubite then I am getting following error : "An unexpected system error has occurred. Additional details have been logged for your administrator."
I tried to add permissions to web application.
$w = Get-SPWebApplication -Identity https://mysp.a.b
$w.GrantAccessToProcessIdentity("Domain\PPS_Account")
It did not help. Thanks in advance!