qperf failure

Hi all,
I'm using qperf to compare TCP & RDMARC performance. qperf report that it failed to modify the QP to RTR status. Does anyone know how to solve the problem?

Host A:nstcloudcc1 configuration:

       nstcc1@nstcloudcc1:tmp$ ib2netdev 
       mlx5_0 port 1 ==> ens261f0 (Up) 173.168.100.103
       mlx5_1 port 1 ==> ens261f1 (Down) 
       nstcc1@nstcloudcc1:tmp$ 
   Host B:rdmarhel0 configuration:
       [rdma@rdmarhel0 tmp]$ ib2netdev 
       mlx5_0 port 1 ==> ens801f0 (Up) 173.168.100.101
       mlx5_1 port 1 ==> ens801f1 (Up) 192.168.100.101
       [rdma@rdmarhel0 tmp]$ 

Run below command on host A as server:

       nstcc1@nstcloudcc1:tmp$ qperf
   Run below command on host B as client:
       [rdma@rdmarhel0 tmp]$ qperf 173.168.100.103 rc_bw
       rc_bw:
       failed to modify QP to RTR: Invalid argument
   The log shows as above on cient that it failed to modify QP to RTR

--Thanks
Changcheng

Does anyone use qperf to compare TCP & RDMA-RC-Send/Recv bandwidth and latency?