standby node installation fail in distributed hana installation

Hi,

today i tried HANA distributed environment setup in our offic.

i want to introduce 3 servers: 1 master, 1 slace and 1 standby o test.

1. i set up a master hana in server A, and startup it

2. i set up a slave in server B through command ./hdbaddhost, which can succesfully communicate with server A.

through hana studio, i find out these 2 nodes succesfully set up a distributed environment

3. last step, i want to create standby node in the same way just like that in server B setup. But it fails and display this errror message

Enter SAP HANA system ID [DS9]:

Enter Shared Installation Path [/hanamnt]:

Enter System Administrator (ds9adm) Password:

Options:

IndexServer role | Description

-------------------------------------------------------------

worker | host is used for database processing

standby | host is idle and available for HA failover

Enter IndexServer role [worker]: standby

add host failed

AddHost not possible. Start SAP HANA Database on master host and run addHost again.

i have double checked that the nameserver in master actually is running and server B also can communicate with server A

it is very appreciate any comments and tips, thanks