Nino_Bilic , there is no link for more information in the output of the health checker, but it's in red. After running the latest EP script the other error ( The current Extended Protection settings may cause issues with some clients types on this protocol.......) disappeared.
As i can remember we did not change the powershell virtual directory and we never saw this error before, after running the EP script the error is still there.
Should i change the powershell virtual directory?
You are right! There was nothing to install only the normal Server 2016 updates.
Well i checked the powershell virtual directory. "Basic authentication was set enabled" i disabled it and run the health checker again and now the error is gone!