Sophos Firewall failed to access web admin console after upgrade from SFOS 19.0.3 MR-3-Build517 to SFOS 19.5.3 MR-3-Build652

After the upgrade, you still able to see the login page:

And also, you able to access Internet via the firewall:

But you failed to login the firewall web console: (Return a blank page)

You able to access firewall via SSH:

Solution:

Use SSH to login, then select "7" , then "R" to reboot the firewall.

Reference:

https://community.sophos.com/sophos-xg-firewall/f/discussions/142061/help-firewall-is-reachable-from-internet-but-not-able-to-connect-to-vpn-or-internal-servers

https://support.sophos.com/support/s/article/KB-000038694?language=en_US#:~:text=Check%20the%20connectivity%20to%20Sophos%20Firewall&text=Otherwise%2C%20try%20to%20access%20the,WAN%20IP%20of%20Sophos%20Firewall.&text=Try%20to%20use%20another%20browser,on%20port%2022%20via%20putty.

Sophos Firewall failed to access web admin console after upgrade from SFOS 19.0.3 MR-3-Build517 to SFOS 19.5.3 MR-3-Build652