ib_write_bw error connecting to server with rdma_cm option

I am trying to run a ib_write_bw test with --rdma_cm(-R) option, the 2 hosts are connected to back to back with infiniband.

I get an error connecting to server. One host has Waiting for client to connect, the other host throws an error:

host1:

>ib_write_bw -R 

************************************
* Waiting for client to connect... *
************************************

host2:

>ib_write_bw -R host1  
Received 10 times ADDR_ERROR 
 Unable to perform rdma_client function 
 Unable to init the socket connection 

The test runs fine without the -R option, any idea why it fails connection with rdma_cm ?