After updating to version 16.1 the website does not come up and shows below error message
Has anyone experienced this and knows how to fix this.  
Thanks

Website landing page shows this Error
Server Error in '/' Application.

Runtime Error

Description: An exception occurred while processing your request. Additionally, another exception occurred while executing the custom error page for the first exception. The request has been terminated.

Looking at Exception log on server I see these entries repeatedly

System.TypeInitializationException The type initializer for 'Rock.Observability.RockMetricSource' threw an exception.
System.UnauthorizedAccessException Access to the registry key 'Global' is denied.

at Microsoft.Win32.RegistryKey.Win32Error(Int32 errorCode, String str)
at Microsoft.Win32.RegistryKey.InternalGetValue(String name, Object defaultValue, Boolean doNotExpand, Boolean checkSecurity)
at Microsoft.Win32.RegistryKey.GetValue(String name)
at System.Diagnostics.PerformanceMonitor.GetData(String item)
at System.Diagnostics.PerformanceCounterLib.GetPerformanceData(String item)
at System.Diagnostics.PerformanceCounterLib.get_CategoryTable() 
at System.Diagnostics.PerformanceCounterLib.CounterExists(String category, String counter, Boolean& categoryExists)
at System.Diagnostics.PerformanceCounterLib.CounterExists(String machine, String category, String counter)
at System.Diagnostics.PerformanceCounter.InitializeImpl()
at System.Diagnostics.PerformanceCounter..ctor(String categoryName, String counterName, String instanceName, Boolean readOnly)
at System.Diagnostics.PerformanceCounter..ctor(String categoryName, String counterName, String instanceName)
at Rock.Observability.RockMetricSource..cctor() in \Rock\Observability\RockMetricSource.cs:line 100"