How to fix the issue when device Web GUI is unable to access

Zyxel_Cooldia

SCENARIO DESCRIPTION:
Somehow, I am unable to access the web GUI of my FLEX/ATP, and the device reboots periodically. Connected serial console to FLEX/ATP, it indicated that httpd is dead, and App watch dog is trying to recover it.

What could be the reason that httpd is dead and what should I do for now?

Console log

SETUP/STEP BY STEP PROCEDURE:
It is because the default certificate of the device corrupts, and the certificate cannot be loaded via http server. When the httpd cannot be recovered by application watchdog in 3 times, the USG will reboot by itself.

In this case, we can regenerate device default certificate by using “Router> debug _ca regenerate”.

VERIFICATION:
After the default certificate is generated, the httpd is recovered by App watch dog and Web GUI is back.

You also can use CLI “Router> debug system ps| match "httpd" to check the httpd status.