Error 108 "Login Failed" - Login Error Code - The Elder Scrolls Online

enlightened First, check the Service Alerts page to see if the servers are undergoing maintenance. enlightened
 
If the servers are currently online, proceed to the following steps:
  1. Check the Official ESO Forums and Bethesda Support Twitter to see if there is anything mentioned. 
  2. Check that the proper exceptions are added to your antivirus/firewall.
  3. If the above does not resolve the issue, ensure the following ports are forwarded on your modem or router:
    • For instructions on how to forward ports, please contact either your ISP (Internet Service Provider) or manufacturer of your modem/router.
      • TCP / UDP Ports 24100 through 24131
      • TCP / UDP Ports 24500 through 24507
      • TCP / UDP Ports 24300 through 24331
      • TCP Port 80
      • TCP Port 433