Problem with Microsoft office sites / IPSEC VPN from pfsense to Sophos

Hi Community,

I really appreciate your help !

I have a problem with openning Microsoft office sites, when the traffic is passing throught an ipsec VPN conection betwenn 2 sites.

Let’s explain the situation.

I have two site, the fisrt with pfsense 2.7 as firewall, the second one is with sophos XG 210 V18.5.

For some reasons , i create a IPSEC VPN site to site from Site Pf to site Sophos for passing internet traffic , so the user who like to connect to internetin site Pf shoud pass from pfsense ->VPN->Sophos navigate internet and return.

In other word the traffic from site PF to internet shoud pass into VPN to sophos , and go to internet , the public ip shoud be the public ip of sophos.

This configuration work perfectly with all sites unless Office and collaboration site (outlook, one drive, sharepoint..).

With some search, i found...