Sitecore CMS not showing graph on Launch pad

This morning when I login to one of none production environment I found that the graph was not loading on Sitecore CMS launch pad.

When I did into more details and found out the ajax request to get the data are failing with server error(HTTP-500). As shown in below image the response of the API call does not providing any information or clue.

Immediately, I jumped onto logs and found following entry in there.

 The remote server returned an error: (403) Forbidden.

The full exception looks like below.

50616 09:48:50 ERROR [Experience Analytics]: System.Net.WebException: The remote server returned an error: (403) Forbidden.
   at System.Net.HttpWebRequest.GetResponse()
   at Sitecore.Xdb.Reporting.Datasources.Remote.RemoteReportDataSourceProxy.GetData(ReportDataQuery query)
   at Sitecore.Xdb.Reporting.ReportDataProvider.c__DisplayClass18_0.b__1()
   at Sitecore.Xdb.Reporting.ReportDataProvider.GetCachedDataForQuery(ReportDataQuery query, Func`1 ifNotAvailableInCache, Nullable`1 ifModifiedSince)
   at Sitecore.Xdb.Reporting.ReportDataProvider.ExecuteQueryWithCache(ReportDataQuery query, ReportDataSource dataSource, CachingPolicy cachingPolicy)
   at Sitecore.Xdb.Reporting.ReportDataProvider.GetData(String dataSourceName, ReportDataQuery query, CachingPolicy cachingPolicy)
   at Sitecore.ExperienceAnalytics.Api.ReportDataService.ExecuteQuery(IReportQueryData queryData, CachingPolicy cachingPolicy)
   at Sitecore.ExperienceAnalytics.Api.ReportingService.RunQuery(ReportQuery reportQuery)
   at Sitecore.ExperienceAnalytics.Api.Http.AnalyticsDataController.Get(ReportQuery reportQuery)


After further investigation found out the Reporting keys were not aligned between CM and Reporting server in the ConnectionStrings.config file.

<add name="reporting.apikey" connectionString="84090dc97055b10532a054da067df368" />

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