NAT to Device behind RED

Hello Community,
I want to add a DNAT Rule to my ASG that forwards a Port on the public IP to a Host behind the RED.

I added the Host behind the Red to my definitions and added the DNAT Rule from Any to Port 85 on the external Interface use DNAT to Host behind RED on Port 80.

This doesn't work at all.
I can see the packet, I can see that the NAT Rule is applied and the traffic seems to be forwarded but nothing happens.

Normally I should see a Webinterface from the Host behind the RED, but this doesn't show up.

Also, I can't see any dropped packets.

When I access the IP from the host behind the NAT in the internal Network everything works, so I can make sure that tunnel etc. works fine.

I use a ASG 120 with 8.305.

Thanks in advance for any help.