SRM5-VM Replication status is "not active "

hi all

          I built the SRM  environment Site A and Site B.

          In Site A, I replication VM to Site B is OK,but in Site B ,I replication VM to Site A,the replication status was "not active".

          When I do replication VM to Site A，the task message showed “configuring Virtual machine replication Setting ....successed”,and I saw the status showed "not active".So,when I tried to synchronize the VM.It told me that "Call "HmsGroup.OnlineSync" for object "GID-4c1a8f01-0883-425c-a49c-a7c872bd6580" on Server "192.168.x.xx" failed.An unknown error has occurred."

          So I did  not know what happened and there was no any log to show the error.