Timeout error when using redis session

I am getting a lot of time out errors after moving our application to redis session state. we usually get either of the following 2 messages:

Timeout performing EVAL (5000ms), next: EVAL, inst: 21, qu: 0, qs: 0, aw: False, bw: SpinningDown, rs: DequeueResult, ws: Idle, in: 0, last-in: 0, cur-in: 54, sync-ops: 579, async-ops: 1, serverEndpoint: xxx.cache.windows.net:6380, conn-sec: 115.79, aoc: 0, mc: 1/1/0, mgr: 9 of 10 available, clientName: wn0sdwk0003PY(SE.Redis-v2.8.0.27420)(Microsoft.Web.RedisSessionStateProvider-v5.1.0.0), IOCP: (Busy=1,Free=999,Min=400,Max=1000), WORKER: (Busy=107,Free=32660,Min=400,Max=32767), v: 2.8.0.27420 (Please take a look at this article for some common client-side issues that can cause timeouts: https://stackexchange.github.io/StackExchange.Redis/Timeouts)

and

Timeout performing EVAL (5000ms), active: EVAL, next: UNKNOWN, inst: 30, qu: 2, qs: 0, aw: True, bw: CheckingForTimeoutComplete, rs: DequeueResult, ws: Writing, in: 0, last-in: 0, cur-in: 20848, sync-ops: 591, async-ops: 1, serverEndpoint: xxx.redis.cache.windows.net:6380, conn-sec: 118.67, aoc: 0, mc: 1/1/0, mgr: 9 of 10 available, clientName: wn0sdwk0003PY(SE.Redis-v2.8.0.27420)(Microsoft.Web.RedisSessionStateProvider-v5.1.0.0), IOCP: (Busy=0,Free=1000,Min=400,Max=1000), WORKER: (Busy=111,Free=32656,Min=400,Max=32767), v: 2.8.0.27420 (Please take a look at this article for some common client-side issues that can cause timeouts: https://stackexchange.github.io/StackExchange.Redis/Timeouts)

and the stack trace:

StackExchange.Redis.RedisTimeoutException: at StackExchange.Redis.ConnectionMultiplexer.ExecuteSyncImpl (StackExchange.Redis, Version=2.0.0.0, Culture=neutral, PublicKeyToken=c219ff1ca8c2ce46) at StackExchange.Redis.RedisDatabase.ScriptEvaluate (StackExchange.Redis, Version=2.0.0.0, Culture=neutral, PublicKeyToken=c219ff1ca8c2ce46) at Microsoft.Web.Redis.StackExchangeClientConnection+<>c__DisplayClass6_0.<Eval>b__0 (Microsoft.Web.RedisSessionStateProvider, Version=5.1.0.0, Culture=neutral, PublicKeyToken=null) at Microsoft.Web.Redis.StackExchangeClientConnection.OperationExecutor (Microsoft.Web.RedisSessionStateProvider, Version=5.1.0.0, Culture=neutral, PublicKeyToken=null) at Microsoft.Web.Redis.StackExchangeClientConnection.RetryLogic (Microsoft.Web.RedisSessionStateProvider, Version=5.1.0.0, Culture=neutral, PublicKeyToken=null) at Microsoft.Web.Redis.StackExchangeClientConnection.Eval (Microsoft.Web.RedisSessionStateProvider, Version=5.1.0.0, Culture=neutral, PublicKeyToken=null) at Microsoft.Web.Redis.RedisConnectionWrapper.TryTakeWriteLockAndGetData (Microsoft.Web.RedisSessionStateProvider, Version=5.1.0.0, Culture=neutral, PublicKeyToken=null) at Microsoft.Web.Redis.RedisSessionStateProvider.GetItemFromSessionStore (Microsoft.Web.RedisSessionStateProvider, Version=5.1.0.0, Culture=neutral, PublicKeyToken=null) at Microsoft.Web.Redis.RedisSessionStateProvider+<GetItemExclusiveAsync>d__19.MoveNext (Microsoft.Web.RedisSessionStateProvider, Version=5.1.0.0, Culture=neutral, PublicKeyToken=null) at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089) at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089) at System.Runtime.CompilerServices.TaskAwaiter1.GetResult (mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089) at Microsoft.AspNet.SessionState.SessionStateModuleAsync+<GetSessionStateItemAsync>d__74.MoveNext (Microsoft.AspNet.SessionState.SessionStateModule, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35) at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089) at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089) at Microsoft.AspNet.SessionState.SessionStateModuleAsync+<AcquireStateAsync>d__65.MoveNext (Microsoft.AspNet.SessionState.SessionStateModule, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35) at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089) at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089) at Microsoft.AspNet.SessionState.TaskAsyncHelper.EndTask (Microsoft.AspNet.SessionState.SessionStateModule, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35) at System.Web.HttpApplication+AsyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a) at System.Web.HttpApplication+<>c__DisplayClass285_0.<ExecuteStepImpl>b__0 (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a) at System.Web.HttpApplication.ExecuteStepImpl (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a) at System.Web.HttpApplication.ExecuteStep (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)

Any ideas on what might be causing these? Thank you

Start with the linked timeout diagnostics and trace the reported path from RedisDatabase.ScriptEvaluate through StackExchangeClientConnection and RedisSessionStateProvider. The issue names no repository file or test and gives no reproduction or acceptance criterion, so first establish a reproducible cause and a verifiable fix.