Cause:

When a job is initiated, the CommServe and client perform. an authentication to verify each other.  The error above indicates a problem has occurred during the authentication process.

In most cases however, this error is the result of a communication problem between the client and CommServe rather than a failure of the actual authentication process.

To begin authentication, the CommServe connects to the client's cvd process on port 8400.  The client then connects back to the CommServe's cvd process, also on port 8400.  If the client is unable to connect back to the CommServe for any reason, the above error will be triggered.  The most common causes are:
 

• Client is unable to resolve the name of the CommServe, or is resolving the name to the wrong address.
   
• Client is unable to reach port 8400 on the CommServe, usually due to a firewall.
   
• Client is attempting to reach the CommServe using the wrong name.  Typically this occurs following a CommServe name change.

Resolution:

Please refer to the following link for a detailed troubleshooting process for Client, CommServe, and Media Agent name resolution issues.

Communication / Connection Problems in the CommCell

Below is a brief recap of the detailed process covered in the link above.

1. From the CommServe, make note of its IP address.
    
2. From the Windows client computer, start regedit.exe.  If the client is running Unix or Linux navigate to the /etc/CommVaultRegistry directory.
    
3. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\CommVault Systems\Galaxy\Instance00x\CommServe and note the value of sCSHOSTNAME.  On a Unix client, go to the Galaxy/Instance00x/CommServe directory.  Open the .properties file with an editor to find the value of sCSHOSTNAME.  This should be the name of the CommServe.  If you have changed the name of your CommServe or the value shown is not the correct name, then correct this value from the client properties page in CommCell Console.
    
4. From the client computer, ping the CommServe using the name as shown in sCSHOSTNAME registry entry above.  Verify that the name resolves to the correct IP address as verified in step 1.  If the client is unable to properly resolve the name of the CommServe, check your DNS and hosts file on the client computer to correct the problem.
    
5. Open up a command prompt from the client computer and enter the following command using the host name exactly as shown in the sCSHOSTNAME registry entry above.  From a Windows client, if the connection succeeds you will see an empty screen.  From a Unix/Linux client, there will be a successful connection message: 

   
   Windows cmd prompt  command
   
   telnet 8400
   
   
   UNIX/Linux command
   
   # telnet 8400
   
   Trying...
   Connected to .
   Escape character is '^]'.
   

If the connection fails, please check your network configuration to ensure that the client computer can properly communicate with the CommServe.