There may be a problem with your 1:1 NAT, as you cannot connect to the
internet on port 25.
I would try to disable the 1:1 NAT and define the 188.8.131.52 address in
the server NAT tab and then do an INbound NAT port 25 from 184.108.40.206 to
192.168.2.2 and check the box to add an automatic firewall rule for