PPPoE WAN don't work with hardware switch but work in physical interface

[CGLOBAL]

I have a problem with a fortigate 40F (firmware : 7.2.10)

I have a connection (LAN) in hardware switch, a second connection (LAN VOIP) in physical interface,

an FTTO link connected to the WAN as backup and an FTTH in PPPoE mode

The problem is i don't have internet (ffth and ftto) behind the LAN, i can't ping google, but i have internet in the LAN VOIP, i don't know why this doesn't work, my policy rules are good.

If i configure my lan in a physical interface and replace the policy rules with the good interface, it's work.

do you have any idea where the problem is coming from ?

[bluebell]

I´ve tried to bridge PPPoE - IF through our building using a dedicated VLAN. This doesn´t work, because PPPoE-IF only uses 2 wires from ethernet/Cat6, the switch-IF doesn´t came up.

My solution is to use a VDSL-Modem. Provider-IF connects to VDSL-Modem(WAN) on cellar-floor, LAN-IF of VDSL-Modem could be bridged through our building using a dedicated VLAN, PPPoE-IF from Fortigate (WAN1) works properly on the 5th floor.