Exception type: NullReferenceException; Exception message: Object reference not set to an instance of an object

Hello Experts,

We encountered some warnings which logged into Event Viewer of CRM Web Server, which indicates Object reference not set to an instance of an object, and operation which caused this warning to logged is something related to Grid refresh, could anyone of you please help us here to find out root cause of an issue;

Error log from Event viewer:

Event code: 3005 Event message: An unhandled exception has occurred.

Exception information: Exception type: NullReferenceException Exception message: Object reference not set to an instance of an object.
at Microsoft.Crm.Core.Application.WebServices.AppGridWebServiceHandler.GetGridDataProvider(String gridXml)
at Microsoft.Crm.Core.Application.WebServices.AppGridWebServiceHandler.Refresh(String gridXml, StringBuilder sbXml, StringBuilder sbHtml, Boolean returnJsonData)
at Microsoft.Crm.Core.Application.WebServices.AppGridWebServiceHandler.ProcessRequestInternal(HttpContext context)

Request information: Request URL: http://<crmorgUrl>/AppWebServices/AppGridWebService.ashx?operation=Refresh Request path: /AppWebServices/AppGridWebService.ashx

Thread information: Thread ID: 45 Is impersonating: False Stack trace: at Microsoft.Crm.Core.Application.WebServices.AppGridWebServiceHandler.GetGridDataProvider(String gridXml)
at Microsoft.Crm.Core.Application.WebServices.AppGridWebServiceHandler.Refresh(String gridXml, StringBuilder sbXml, StringBuilder sbHtml, Boolean returnJsonData)
at Microsoft.Crm.Core.Application.WebServices.AppGridWebServiceHandler.ProcessRequestInternal(HttpContext context)
Custom event details: