Forticlient access VPN problem via Windows11

[Clem2024]

Hi,

Laptop using Forticlient 7.x VPN on Windows 11Home for a year, so far is OK, recently, I have been unable to access the IPSec VPN from my laptop. Each time I attempt to log in, FortiClient displays the error message 'IPsec VPN connection is down.' When I check the FortiClient log, the last entry reads 'Phase1 retransmit reaches maximum count.'

I also tried accessing the IPSec VPN on other branch office FortiGate firewall (model 61F) using FortiClient, but the same error message appeared.

Laptop

Win11Home, Forticlient 7.x

Firewall

FortiGate 30E, firmware v5.4x

FortiGate 61F, firmware v7.2x

Can someone help? Thanks in advance.

Clement

[fogilvom2]

Do you have "Use external browser as user agent for saml authentication" checked in the connection settings? If not, that may be worth a try. That's resolved some of the -6005 errors we've seen.

[Clem2024]

How can I find the "user external browser...." from the Forticlient agent, there is no such item from the settings.

[AEK]

Hello Clement

Can you check with the remote FGT admin if he is receiving your connection attempts?

diag vpn ike log-filter name tunnel_name
diag debug application ike -1
diag debug enable

Hope it helps.

[Clem2024]

Thanks AEK,

I will follow your instructions and test it again but I think that maybe the laptop Windows 11 problem or driver problem because I have tried to use other computers to access VPN to above two firewalls and the result were positive, no any problem, I am not sure if it is Windows 11 problem or driver problem as my other computers are running Windows 10.

[AEK · Accepted solution]

Hi Clem

I confirm I've seen many similar issues related to NIC driver. Some have been fixed by either a driver downgrade or update or change.

[Clem2024]

Thanks AEK,

My laptop Win11 is MS Surface laptop, not sure if it is easy to downgrade the driver, but I will try it and revert.