Troubleshooting Tip: How to solve Backup DNS Failed error on FortiClient on Ubuntu 22.04

[Koushik_IND_Banglore]

Description	This article provides the workaround for the error 'Backup DNS Failed' on FortiClient on Ubuntu 22.04.
Scope	FortiClient.
Solution	When using FortiClient on Ubuntu 22.04, the user may get the following error while trying to connect to SSL VPN: Backup DNS Failed. When this error is seen the VPN connection will fail most of the time. In the FortiClient debug logs the following traces will be visible: 11:07:20.998 TZ=+0200 [sslvpn:INFO] main:1456 State: Configuring tunnel 11:07:21.068 TZ=+0200 [sslvpn:DEBG] vpn_util:260 Get connection name: ????????? ?????????? 1 11:07:21.068 TZ=+0200 [sslvpn:DEBG] vif:98 Using nmcli to allocate tun device. 11:07:21.367 TZ=+0200 [sslvpn:DEBG] dns:274 Default route device name: enxc8f750b40f75 11:07:21.430 TZ=+0200 [sslvpn:DEBG] vpn_util:260 Get connection name: ????????? ?????????? 1 11:07:21.430 TZ=+0200 [sslvpn:DEBG] dns:286 DNS backup 11:07:21.496 TZ=+0200 [sslvpn:DEBG] vpn_util:234 Get auto DNS setting failed. 11:07:21.496 TZ=+0200 [sslvpn:EROR] vpn_connection:1634 Backup DNS failed <------ When this issue is observed, the network/WiFi connection details between the PC (on which FortiClient is installed) and the internal router/ISP modem/cellphone hotspot need to be checked. Mostly this error will be seen with a WiFi/SSID connection. To resolve the issue check that the SSID name has no accents or spaces (UTF-8 characters), if it has, then rename it without any accents or spaces or UTF-8 characters which will resolve the issue.