I think that the line
<m2n:sockets from="Fluid" to="Solid" exchange-directory=".." />
could be critical in your case.
We would need to know exactly how you start the solvers. Do you start them using the supplied scripts or manually? The paths from where you start the simulation matter. Therefore, you might have for the adapt the
exchange-directory setting such that the solver can find each other.
If you run the participants in parallel and on more than one node than you have to add a network setting to this line. preCICE is by default using the loopback interface
lo. This means your current configuration file is equivalent to changing the line to the following:
<m2n:sockets from="Fluid" to="Solid" exchange-directory=".." network="lo" />
In order to use another network device you need to give the name of the relevant network interface for communication, i.e. replace
lo by another name. You can find network interfaces using the command
ip link which gives you the name of the network cards available. One of the name will be
lo. Other common names are something like
eth1 etc. On bigger clusters it could also be
ib0 or so (infiniband).