The Web Service plug-in failed in OrganizationId and Unhandled Exception: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation

Hi All,
We are receiving below errors in our production envrionment as
 
The Web Service plug-in failed in OrganizationId: c28f361a-8111-e211-b7f2-68b599c03df8; SdkMessageProcessingStepId: 36ccbb1b-ea3e-db11-86a7-000a3a5473e8; 

 
1.
EntityName: userquery; Stage: 30; MessageName: RetrieveMultiple; 

Exception: Unhandled Exception: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation
Inner Exception: System.IndexOutOfRangeException: #TotalRecordCount<Data>Unhandled Exception: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
Inner Exception: System.IndexOutOfRangeException: #TotalRecordCount
2.
EntityName: email; Stage: 30; MessageName: RetrieveMultiple

Exception: Unhandled Exception: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation
Inner Exception: System.NullReferenceException: Object reference not set to an instance of an object<Data>Unhandled Exception: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation
Inner Exception: System.NullReferenceException: Object reference not set to an instance of an object.
3.
EntityName: plugintype; Stage: 30; MessageName: RetrieveMultiple; 

<Data>Unhandled Exception: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
Inner Exception: System.InvalidOperationException: There is already an open DataReader associated with this Command which must be closed first.
 Exception: Unhandled Exception: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
Inner Exception: System.InvalidOperationException: There is already an open DataReader associated with this Command which must be closed first
Please give us idea on above issues.

Natarajan.V