I've seen this error at my my log.
System.AggregateException: One or more errors occurred. ---> System.Threading.Tasks.TaskCanceledException: A task was canceled.
--- End of inner exception stack trace ---
at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
at System.Threading.Tasks.Task`1.get_Result()
at SmartStore.Admin.Controllers.CommonController.<>c__DisplayClass24_0.<CheckUpdateInternal>b__0()
---> (Inner Exception #0) System.Threading.Tasks.TaskCanceledException: A task was canceled.<---