Exchange Server 2016: Server Error in '/ecp' Application - exchange-server

Question

I am getting error in the ECP of Exchange Server 2016 while the OWA is working fine. The ECP login page opens but after login we get following error. This issue has been for around a week and we have not made any progress. Please assist if anyone has face similar error and resolved the issue.
Server Error in '/ecp' Application.
Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.
Source Error:
The source code that generated this unhandled exception can only be shown when compiled in debug mode. To enable this, please follow one of the below steps, then request the URL:
1. Add a "Debug=true" directive at the top of the file that generated the error. Example:
<%# Page Language="C#" Debug="true" %>
or:
2) Add the following section to the configuration file of your application:
<configuration>
<system.web>
<compilation debug="true"/>
</system.web>
</configuration>
Note that this second technique will cause all files within a given application to be compiled in debug mode. The first technique will cause only that particular file to be compiled in debug mode.
Important: Running applications in debug mode does incur a memory/performance overhead. You should make sure that an application has debugging disabled before deploying into production scenario.
Stack Trace:
[NullReferenceException: Object reference not set to an instance of an object.]
Microsoft.Exchange.Management.ControlPanel.Global..cctor() +119
[TypeInitializationException: The type initializer for 'Microsoft.Exchange.Management.ControlPanel.Global' threw an exception.]
ASP.global_asax..ctor() +28
[TargetInvocationException: Exception has been thrown by the target of an invocation.]
System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck) +0
System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark) +139
System.Activator.CreateInstance(Type type, Boolean nonPublic) +105
System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes, StackCrawlMark& stackMark) +1431
System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes) +184
System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture) +27
System.Web.HttpRuntime.CreateNonPublicInstance(Type type, Object[] args) +79
System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context) +178
System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext) +341
[HttpException (0x80004005): Exception has been thrown by the target of an invocation.]
System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +523
System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +107
System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +688
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.3770.0