Unknown SQL Exception 64 occurred. Additional error information from SQL Server is included below. A transport-level error has occurred when receiving results from the server

hi

in one of web front end server  this below error appears since last day

Log Name:      Application

Source:        Microsoft-SharePoint Products-SharePoint Foundation

Date:          11/16/2015 8:45:37 AM

Event ID:      5586

Task Category: Database

Level:         Error

Keywords:     

User:          XXXPORTAL\spfarm

Computer:      XXXWFE02.xxxportal.com

Description:

Unknown SQL Exception 64 occurred. Additional error information from SQL Server is included below.

A transport-level error has occurred when receiving results from the server. (provider: TCP Provider, error: 0 - The specified network name is no longer available.)

    <Data Name="int0">64</Data>

    <Data Name="string1">A transport-level error has occurred when receiving results from the server. (provider: TCP Provider, error: 0 - The specified network name is no longer available.)</Data>

  </EventData>

</Event>

adil