Create an IPSec tunnel between Windows Server and pfSense

  • I've been trying to create a tunnel between my office LAN and home LAN :

    Office Network :
    Windows Server 2019 (Directly connected to WAN, RDP Access) : ADDS/WAN/Web Server/ROUTER
    Office LAN :
    --> CentOS (running EMR/Accounting Software for my Clinic)
    --> Office Desktop
    --> Office NAS

    Home Network
    pfSense (connected directly to WAN)
    Home LAN :
    --> Windows Server 2019 (ADDS)
    --> Home NAS
    --> Home Computers

    I was able to successfully set up a site to site IPSec VPN between the two Windows Server by forwarding the ports on pfSense. But I want my entire office subnet to be accessible by any device behind my pfSense box at home.

    I created a similar tunnel between the pfSense box and the office Windows Server 2019 computer, and the tunnel comes up successfully when pfSense initiates it.

    However when I try to initiate the tunnel from Windows Server 2019, it shows an error : "Invalid Payload Received".

    What am I doing wrong ?

    Phase 1.png Phase 2.png Session.png

    Error on Windows Server : err.png
    (Logs just show connection failed with unknown error 22)

    (Apologies for any critical error, I'm a total noob.
    I am a junior doctor, having been quarantined for the COVID-19 Crisis, I need to access files from my office in order to create lecture slides).