Why my switch shows “Upgrade system firmware failed” in the event log?

Zyxel_Melen Posts: 1,748  Zyxel Employee
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Some users might have firmware upgrade failures after clicking the upgrade now button on the firmware management page or Nebula automatically upgrades. This topic is to guide Nebula users to troubleshoot this problem.


  1. Please check if the DNS server used by your switch can resolve the domain name "firmware.nebula.zyxel.com."
  2. Please make sure there are no firewall policies restricting access to “firmware.nebula.zyxel.com” “port 443”.
  3. If the firewall does not block, please collect tech support and contact Zyxel support for help.

You can reference this FAQ to contact Zyxel support via Nebula.

Zyxel Melen