The database is in the restricted mode. In my case, It is in the nomount
select logins from v$instance;
We can check the listener status and it shows BLOCKED hence we can not connect it form remote.
Update the listener.ora on the AUX DB ( oradb2) then restart the listener
(SID_NAME = oradb2)
(ADDRESS = (PROTOCOL = TCP)(HOST = panda2.localdomain)(PORT = 7001))
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC7001))
I found some other blog post for adding the (UR=A) in the tnsname.ora. In my testing, it does not seems to work on 11g. ( I am using non default port).