Pfsense Dual WAN port forwarding fail

I have a Pfsense router at my friend bussiness site. He have a redundent internet connection:
WAN: 50/50 pppoe fiber whit public IP, used for everything.
WAN2: LTE (under nat) , used for only backup when the main WAN unavailable.

We need port forwarding one port over WAN for our PRTG monitoring solution. We try everything but something weird thing block the access.

(We try it this PRTG VM at my side and the port forwarding works so, not the Windows Server firewall the problem.)

This is the pfsense firewall config:

I checked the forwarding and from the outside request arrived to the router…:

Any idea what we screwed up? :smiley:

Thank you in advance!