Database mirroring on SQL Server 2005: The server network address "TCP://192.168.50.34:7022" can not be reached or does not exist. Check the network address name and reissue the command.'

Hi Experts,

I am setting  database mirroring on SQL Server 2005 . I encountered the error :'The server network address "TCP://192.168.50.34:7022" can not be reached or does not exist. Check the network address name and reissue the command.'

I have set database mirroring as belows:
--Principal server: nangdd-s02.ncs.com.vn
--Mirror server: ncs-e5ra7wreska.ncs.com.vn
 
1) Creat database AdventureWorks on principal server (nangdd-s02.ncs.com.vn)
 
2)Modify it to use the full recovery model:
USE master;
GO
ALTER DATABASE AdventureWorks
SET RECOVERY FULL;
GO
 
3)create a full backup of the principal database as follows:
BACKUP DATABASE AdventureWorks
    TO DISK = 'C:\AdventureWorks.bak'
    WITH FORMAT
GO
 
4)Copy the full backup to the mirror server (ncs-e5ra7wreska.ncs.com.vn) and restore the full backup WITH NORECOVERY onto the mirror server instance.
RESTORE DATABASE AdventureWorks
    FROM DISK = 'C:\AdventureWorks.bak'
    WITH NORECOVERY
GO
 
5)create a log backup on the principal database.
BACKUP LOG AdventureWorks
    TO DISK = 'C:\AdventureWorks_Log1.bak'
GO
 
6)Copy the backup log file to the mirror server and restore log
RESTORE LOG AdventureWorks
    FROM DISK = 'C:\AdventureWorks_Log1.bak'
    WITH FILE=1, NORECOVERY
GO
 
7)On the principal server instance create an endpoint that supports all roles using port 7022:
CREATE ENDPOINT Endpoint_Mirroring
    STATE=STARTED
    AS TCP (LISTENER_PORT=7022)
    FOR DATABASE_MIRRORING (ROLE=ALL)
GO
 
8) On the principal server instance create Window Login to Pirror database from Principal server
USE master;
GO
CREATE LOGIN [BUILTIN\Administrators] FROM WINDOWS;
GO
GRANT CONNECT on ENDPOINT::Mirroring_Endpoint TO [BUILTIN\Administrators];
GO
 
9)On the mirror server instance  create an endpoint that supports all roles using port 7022:
CREATE ENDPOINT Endpoint_Mirroring
    STATE=STARTED
    AS TCP (LISTENER_PORT=7022)
    FOR DATABASE_MIRRORING (ROLE=ALL)
GO
GRANT CONNECT on ENDPOINT::Endpoint_Mirroring TO [ncs\s02nangdd];
GO
 
10) On the mirror server create Window Login to Principal database from Mirror server
USE master;
GO
CREATE LOGIN [ncs\s02nangdd] FROM WINDOWS;
GO
GRANT CONNECT on ENDPOINT::Mirroring_Endpoint TO [ncs\s02nangdd];
GO
 
11) On the principal server instance, back up the database:
GO
BACKUP DATABASE AdventureWorks
    TO DISK = 'C:\AdventureWorks_dbmirror.bak'
    WITH FORMAT
GO
 
12)Copy backup file to the mirror server instance , restore the database:
RESTORE DATABASE AdventureWorks
    FROM DISK = 'C:\AdventureWorks_dbmirror.bak'
    WITH NORECOVERY
GO
 
13) Create a log backup on the principal database
BACKUP LOG AdventureWorks
    TO DISK = 'C:\AdventureWorks_Log2.bak'
GO
 
14)Copy log backup file to the mirror server instance and restore:
RESTORE LOG AdventureWorks
    FROM DISK = 'C:\AdventureWorks_Log2.bak'
    WITH FILE=1, NORECOVERY
GO
 
15) On the mirror server instance, set the server instance on nangdd-s02.ncs.com.vn as the partner
ALTER DATABASE AdventureWorks
    SET PARTNER =
    'TCP://nangdd-s02.ncs.com.vn:7022'
GO
 
16)On the principal server instance, set the server instance on  as the partner
ALTER DATABASE AdventureWorks
    SET PARTNER = 'TCP://ncs-e5ra7wreska.ncs.com.vn:7022'
GO
 
The first 15 steps well done!
But after step 16 I am receiving the following error:
'Msg 1418, Level 16, State 1, Line 1
The server network address "TCP://192.168.50.34:7022" can not be reached or does not exist. Check the network address name and reissue the command.'
I have check network address, firewall, port availability but I still receive the same error
Anyone help me please!

Thanks,
NCS