Connecting to FortiClient VPN results in no internet

Hey there, first-time poster. Apologies, I'm not very familiar with networking or FortiClient, please for give any misunderstandings.

I'm on Windows 10, trying to use the FortiClient VPN to connect to an IPsec VPN with a pre-shared key. Have tried this over both Wifi and Ethernet.

I'm able to connect to the VPN, but whenever I connect, I notice that my internet connection changes from "Connected, secured", to "Connected, no internet", and I entirely lose my ability to use internet access when connected to the VPN.

Please let me know if there's any more information I could provide, or what steps to take next.

Note: About 6 months ago, this process was working fine. In that time, I had moved my modem to a different outlet in my house, and had re-configured which frequency my Wifi was on. However, I can't say conclusively if that caused this issue. I've factory reset my modem and moved it back to the original outlet, but still no luck.