NullReferenceException in RedisGrainDirectory

[alrz]

Failed to address message Request [S10.42.89.175:11111:72274570 sys.svc.user.95B6CAE6/10.42.89.175:11111@72274570]->[ management/0] Orleans.Runtime.IManagementGrain.GetRuntimeStatistics(Orleans.Runtime.SiloAddress[]) #477

System.NullReferenceException: Object reference not set to an instance of an object.
   at Orleans.GrainDirectory.Redis.RedisGrainDirectory.Lookup(GrainId grainId) in /_/src/Redis/Orleans.GrainDirectory.Redis/RedisGrainDirectory.cs:line 45
   at Orleans.Runtime.GrainDirectory.CachedGrainLocator.Lookup(GrainId grainId) in /_/src/Orleans.Runtime/GrainDirectory/CachedGrainLocator.cs:line 55
   at Orleans.Runtime.Placement.PlacementService.PlacementWorker.GetOrPlaceActivationAsync(Message firstMessage) in /_/src/Orleans.Runtime/Placement/PlacementService.cs:line 364
   at Orleans.Runtime.Messaging.MessageCenter.<AddressAndSendMessage>g__SendMessageAsync|39_0(Task addressMessageTask, Message m) in /_/src/Orleans.Runtime/Messaging/MessageCenter.cs:line 471

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Lookup failed for management/0

System.NullReferenceException: Object reference not set to an instance of an object.
   at Orleans.GrainDirectory.Redis.RedisGrainDirectory.Lookup(GrainId grainId) in /_/src/Redis/Orleans.GrainDirectory.Redis/RedisGrainDirectory.cs:line 45
   at Orleans.Runtime.GrainDirectory.CachedGrainLocator.Lookup(GrainId grainId) in /_/src/Orleans.Runtime/GrainDirectory/CachedGrainLocator.cs:line 55
   at Orleans.Runtime.Placement.PlacementService.PlacementWorker.GetOrPlaceActivationAsync(Message firstMessage) in /_/src/Orleans.Runtime/Placement/PlacementService.cs:line 364
   at Orleans.Runtime.Messaging.MessageCenter.<AddressAndSendMessage>g__SendMessageAsync|39_0(Task addressMessageTask, Message m) in /_/src/Orleans.Runtime/Messaging/MessageCenter.cs:line 471