Lost connection between DB server and Application server

Hi All

We had an incident in the production environment today.

We have a DB Server and a desktop client in the Application server. The client told us the desktop client can't connect to the DB server.

I logged to the Application server and did a test. I had the same issue, pinged the DB server and it seem fine.

And within few seconds it seem to work okay

Windows event viewer gave me these errors

 Code = 0x80004005
 Code Meaning = [DBNETLIB][ConnectionOpen (Connect()).]SQL Server does not exist or access denied.

 Code = 0x800a0e7d
 Code Meaning = The connection cannot be used to perform this operation. It is either closed or invalid in this context.

Is this just because of network connection?

Is there anyway to capture in any of the logs to know exactly what happen?

Thanks