The following error message can occur when starting Fluent while being connected to a VPN: [proxy:0:0@hostname] ..\hydra\utils\sock\sock.c (270): unable to connect from “hostname” to “hostname.domainname” (No error) [proxy:0:0@hostname] ..\hydra\pm\pmiserv\pmip.c (468): unable to connect to server hostname.domainname at port 53321 (check for firewalls!) where “hostname” is the name of your local machine and domainname is the name of the domain you are connected to. This is a known issue when using the “intel” MPI method. In the Fluent Launcher in the tab “Parallel Settings” set MPI Types = msmpi Select IP Interface = 127.0.0.1 in which 127.0.0.1 is your local machine.