troubleshooting Question

Weird ASYNC_NETWORK_IO error happening in SQL Server on VM

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purplesoupFlag for United Kingdom of Great Britain and Northern Ireland asked on
Microsoft SQL ServerNetworkingASP.NETMicrosoft Server OSVirtualization
3 Comments1 Solution209 ViewsLast Modified:
We create VMs with the latest build of our code on. One VM has a weird ASYNC_NETWORK_IO error when running a SQL SELECT statement. It isn't on any other VM.

I have tried googling for the error - clearly something failed to start or get set when this VM was created.

Just for peace of mind it would be really useful to know what might be the cause of this and if there is some setting I can adjust to fix it.

The symptom is that a SQL SELECT statement just seems to time out with this ASYNC_NETWORK_IO error, but the strange thing is that it must have somehow returned some results because it then blocks an INSERT statement that has used the results of the SELECT statement.

Everything necessary for the application is on the VM - the ASP.NET application and the SQL Server database so there is no actual network access outside of the VM.

There is no antivirus running on the VM either which is one possibly cause I came across.

The server is Windows Server 2016 and the SQL Server is 2016 also.

I've attached a picture of what is happening.

Just to repeat this doesn't occur on any other VMs with the same software on.

I have tried restarting IIS and restarting the VM.

The VM is Hyper-V.

ASYNC_NETWORK_IO error
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