DBMRFC session mode error

hi,

When I use DB59 to test connect,  it always said there is an error.

Application Server:  dga115_AT6_02                            ( AIX        )

   1. Connect. test with "dbmcli db_state"                         Successful

   2. Connect. test with command mode "dbmrfc db_state"            Successful

   3. Connect. test with session mode "dbmrfc db_state"            Unsuccessful

      communication_failure

      Name and Server     : LT6 - dga115

      DBMRFC Function     : DBM_CONNECT

      Error               : Communication Error

      Error Message       : Error when opening an RFC connection

   4. Connect. test with "native SQL"  ( LCA )                     Successful

I try to run dbmrfc using user lt6adm, no error appear. And

dbmcli -n dga115 -d LT6 -u control,sap2cool db_state

OK

State

ONLINE

Can you help me?

Thanks a lot!

Best Regards,

Lily