What can be the reason of connection down for ASPNET.CORE App in IIS?

Question

Web have a web app ASPNET.Core 3.1 running on IIS. Load Balancer and two servers are running as system architecture. Sometimes below log is created no clients can access to application and we couldn't figured out why. Servers are up, network trace logs, CPU and RAM usage seems normal, but browser spinner is turning forever. After a couple of minutes system can be accessible. By the way, all anti-virus services disabled.

 2022-03-08 01:23:29.0823 | AirClinicIIS |  |  | INFO|JSNLog.JSNLogMiddleware | JSNLog: Exception while processing log request -  Microsoft.AspNetCore.Connections.ConnectionResetException: The client has disconnected
System.Runtime.InteropServices.COMException (0x80070040): The specified network name is no longer available. (0x80070040)
   --- End of inner exception stack trace ---
   at Microsoft.AspNetCore.Server.IIS.Core.IO.AsyncIOOperation.GetResult(Int16 token)
   at Microsoft.AspNetCore.Server.IIS.Core.IISHttpContext.ReadBody()
   at System.IO.Pipelines.PipeCompletion.ThrowLatchedException()
   at System.IO.Pipelines.Pipe.GetReadResult(ReadResult& result)
   at System.IO.Pipelines.Pipe.ReadAsync(CancellationToken token)
   at System.IO.Pipelines.Pipe.DefaultPipeReader.ReadAsync(CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Server.IIS.Core.IISHttpContext.ReadAsync(Memory`1 memory, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Server.IIS.Core.HttpRequestStream.ReadAsyncInternal(Memory`1 buffer, CancellationToken cancellationToken)
   at System.IO.StreamReader.ReadBufferAsync(CancellationToken cancellationToken)
   at System.IO.StreamReader.ReadToEndAsyncInternal()
   at JSNLog.JSNLogMiddleware.ProcessRequestAsync(HttpContext context)
   at JSNLog.JSNLogMiddleware.Invoke(HttpContext context)  | url: https://acom.airclinic.com.tr/jsnlog.logger | action: 

We have another log below maybe gives idea

2022-03-08 01:24:46.2159 | AirClinicIIS |  | 1 | ERROR|Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware | An unhandled exception has occurred while executing the request. Microsoft.AspNetCore.Connections.ConnectionResetException: The client has disconnected
System.Runtime.InteropServices.COMException (0x800704CD): An operation was attempted on a nonexistent network connection. (0x800704CD)
       --- End of inner exception stack trace ---
       at Microsoft.AspNetCore.Server.IIS.Core.IO.AsyncIOOperation.GetResult(Int16 token)
       at Microsoft.AspNetCore.Server.IIS.Core.IISHttpContext.ReadBody()
       at System.IO.Pipelines.PipeCompletion.ThrowLatchedException()
       at System.IO.Pipelines.Pipe.GetReadResult(ReadResult& result)
       at System.IO.Pipelines.Pipe.ReadAsync(CancellationToken token)
       at System.IO.Pipelines.Pipe.DefaultPipeReader.ReadAsync(CancellationToken cancellationToken)
       at Microsoft.AspNetCore.Server.IIS.Core.IISHttpContext.ReadAsync(Memory`1 memory, CancellationToken cancellationToken)
       at Microsoft.AspNetCore.Server.IIS.Core.HttpRequestStream.ReadAsyncInternal(Memory`1 buffer, CancellationToken cancellationToken)
       at Microsoft.AspNetCore.WebUtilities.FileBufferingReadStream.ReadAsync(Byte[] buffer, Int32 offset, Int32 count, CancellationToken cancellationToken)
       at Microsoft.AspNetCore.WebUtilities.StreamHelperExtensions.DrainAsync(Stream stream, ArrayPool`1 bytePool, Nullable`1 limit, CancellationToken cancellationToken)
       at Microsoft.AspNetCore.Mvc.Formatters.NewtonsoftJsonInputFormatter.ReadRequestBodyAsync(InputFormatterContext context, Encoding encoding)
       at Microsoft.AspNetCore.Mvc.ModelBinding.Binders.BodyModelBinder.BindModelAsync(ModelBindingContext bindingContext)
       at Microsoft.AspNetCore.Mvc.ModelBinding.ParameterBinder.BindModelAsync(ActionContext actionContext, IModelBinder modelBinder, IValueProvider valueProvider, ParameterDescriptor parameter, ModelMetadata metadata, Object value)
       at Microsoft.AspNetCore.Mvc.Controllers.ControllerBinderDelegateProvider.<>c__DisplayClass0_0.<<CreateBinderDelegate>g__Bind|0>d.MoveNext()
    --- End of stack trace from previous location where exception was thrown ---
       at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeInnerFilterAsync>g__Awaited|13_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
       at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResourceFilter>g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
       at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
       at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
       at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()
    --- End of stack trace from previous location where exception was thrown ---
       at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
       at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
       at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
       at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
       at Microsoft.AspNetCore.Session.SessionMiddleware.Invoke(HttpContext context)
       at Microsoft.AspNetCore.Session.SessionMiddleware.Invoke(HttpContext context)
       at AirClinic.ACOM.Web.Middleware.GenericMiddleware.Invoke(HttpContext httpContext) in D:\Air Clinic Backup\Projects\Git\AirClinicOperationManagementSystem\AirClinic.ACOM.Web\Middleware\GenericMiddleware.cs:line 44
       at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.<Invoke>g__Awaited|6_0(ExceptionHandlerMiddleware middleware, HttpContext context, Task task) | url: https://acom.airclinic.com.tr/PassengerData/Delete | action: Delete