Are you facing below mentioned xConnect error? Not able to find out the possible cause and fix?
Well, one of my colleague was struggling with this error on Processing Server. Log files were full of below mentioned error. 8556 13:04:06 ERROR Exception when executing agent aggregation/aggregator Exception: Sitecore.XConnect.XdbCollectionUnavailableException Message: An error occurred while sending the request. Source: Sitecore.XConnect.Client at Sitecore.XConnect.Client.WebApi.CollectionBatchWebApiClient.<ExecuteBatch>d__11.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Sitecore.XConnect.Client.Operations.HttpOperationInvoker.<Execute>d__8.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Sitecore.XConnect.XdbContext.<ExecuteBatchAsyncInternal>d__79.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at Sitecore.XConnect.XdbContext.<ExecuteBatchAsyncInternal>d__79.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Sitecore.XConnect.XdbContext.<ExecuteAsync>d__72.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Sitecore.XConnect.XdbContext.<GetAsync>d__35`1.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Sitecore.Analytics.Processing.AsyncPoolScheduler`2.<TryGetNextAsync>d__14.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Sitecore.Analytics.Aggregation.InteractionAggregationAgent.<ExecuteCoreAsync>d__15.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Sitecore.Analytics.Core.Agent.<ExecuteAsync>d__1.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Sitecore.Analytics.Core.AsyncBackgroundService.<ExecuteAgentAsync>d__22.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Sitecore.Analytics.Core.AsyncBackgroundService.<RunAsync>d__26.MoveNext() Nested Exception Exception: Sitecore.Xdb.Common.Web.ConnectionTimeoutException Message: A task was canceled. Source: Sitecore.Xdb.Common.Web at Sitecore.Xdb.Common.Web.CommonWebApiClient`1.<ExecuteAsync>d__37.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Sitecore.XConnect.Client.WebApi.CollectionBatchWebApiClient.<ExecuteBatch>d__11.MoveNext() Nested Exception Exception: System.Threading.Tasks.TaskCanceledException Message: A task was canceled. Source: mscorlib at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Sitecore.Xdb.Common.Web.CommonWebApiClient`1.<ExecuteAsync>d__37.MoveNext() This seems Scaling issue as the error was now completely disappeared after scaling up. So try scaling up your instance to get rid of such issue. Thanks to my colleague Thom for sharing this resoultion! Let me know if you find any other resolution.