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RedisServerException "ERR command is not allowed" after v3.4.0 update #3274
Description
Since we upgraded to v3.4.0 we observe exceptions with error message Encountered error while updating cluster config: ERR command is not allowed and call stack:
StackExchange.Redis.RedisServerException:
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter.GetResult (System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at StackExchange.Redis.ConnectionMultiplexer+<GetEndpointsFromClusterNodes>d__176.MoveNext (StackExchange.Redis, Version=3.0.0.0, Culture=neutral, PublicKeyToken=c219ff1ca8c2ce46: /_/src/StackExchange.Redis/ConnectionMultiplexer.cs:2165)
We are using Azure Managed Redis non-clustered resource which might be the reason for the observed exception. Downgrading to v3.3.1 fixes the issue.
Activity
mgravell commentedon Oct 13, 2026
OK; I'll investigate as a priority. Did this occur when connecting? Or when issuing some explicit command? Or perhaps during reshard? Any context, basically, so I can try find and resolve as quickly as possible.
Anecdotally, I did explicitly test this release on AMR (which isn't a strict rule), but I tested on an AMR cluster, since I was especially interested in the cluster side of things. Hey @philon-msft - is there a budget case in here somewhere of MSFT sponsoring a low tier (I don't need much compute or storage) set of endpoints for me to verify at least connect and basic ops of both AMR cluster and standalone during CI?
mgravell commentedon Oct 13, 2026
(I've delisted 3.4.0 while we investigate; I aim to ship a 3.4.4 or whatever today, at which point I'll relist 3.4.0 for historic purposes)
vladislav-karamfilov commentedon Oct 13, 2026
@mgravell , thank you for prioritizing this! Unfortunately, this is all the info we have in Application Insights. I suspect this is related to the SignalR connections for which we use Redis as a backplane because I don't see any application code being executed in the error report.
Tolerate refused CLUSTER SLOTS/NODES during topology updates (#3275)
mgravell commentedon Oct 13, 2026
This should be fixed by #3275, in v3.4.5