Thanks for your help !
I finally got it to work but honestly not really sure what was the issue.
On my pfsense2 i changed the LAN ip and the WAN IP.
In the NAT rule i changed several times back and forth the translation address from interface address to 192.168.0.2, rebooted the Humax modem and it worked finally.
When i turn off the pfsense1 i will keep having internet with pfsense2, when pfsense 1 is back online it is still working as well…
I think this is solved.
Thanks a lot for your help and sorry i bothered you with this !