3101

Most common reason

  • Password has expired or the account is locked out

SMTP authentication error

  • Consult with your mail administrator to verify that the login account name and password required for SMTP authentication is correct

Is the server operating correctly?

  • Make sure that the network environment (server, hub, or other LAN network) is operating correctly

Is the correct authentication method set as the same as the destination computer?

  • Check the settings on the server and client
  • (For example, make sure the SMTP/POP authentication enable/disable settings are the same on the server and on the client.)