Can't add NDMP filer on NetBackup Admin Console

Hi guys

I have a problems when try to add NDMP filer by Configure Storage Devices on NetBackup Administration Console. One of my NAS failed to add show message as a below picture. 

I have four NAS devices on network system but the other three can add without any problem. All NAS use the same credential.

I try to use tpautoconf and tpconfig command verify and add filer but it also failed.

I can telnet with port 10,000 from Master Server to NAS and ndmpd services on NAS is also on.

My Master Server is Windows Server 2008 R2 SP2 Enterprise with NetBackup 7.6.0.1

Media Server is NetBackup Appliance 5220 with NetBackup 2.6.0.1

I can't find out what is the cause this problem. Could someone help me fix it?

Thank you