Flush DNS cache failed and Backup routing table failed on Ubuntu 20.04

[networknoob]

I am able to establish a VPN connection, but I immediately get disconnected from the VPN a few seconds later. I believe that connecting to the VPN is causing my WiFi to disconnect, but I am not sure if this is what's actually happening.

I am on Ubuntu 20.04.6. I downloaded the Debian client directly from the Fortinet website. I have been able to connect to the VPN fine on Windows/Mac computers, so I don't think it's an issue authentication issue, especially since I am passing the authentication phase on the Linux.

So far, I have tried to disable IPv6 and the local Ubuntu firewall, but I am still experiencing the same issue.

Here are the device logs showing the errors for "Flush DNS cache failed" and "Backup routing table failed"

20230405 21:01:00.765 [sslvpn:DEBG] dns:149 Restart DNS service successfully.
20230405 21:01:00.767 [sslvpn:DEBG] dns:161 Flush DNS cache failed.
20230405 21:01:00.767 [sslvpn:DEBG] route:99 route backup START
20230405 21:01:00.767 [sslvpn:DEBG] route:109 No gateway found for 1.1.1.1
20230405 21:01:00.767 [sslvpn:DEBG] route:127 No gateway found for [VPN IP]
20230405 21:01:00.767 [sslvpn:DEBG] route:151 route backup DONE
20230405 21:01:00.767 [sslvpn:EROR] vpn_connection:1296 Backup routing table failed

[gfleming]

Which version of FortiClient? Which version of FortiOS? Are you doing split tunnel or full tunnel?