Building Auxiliary database from Primary

Hi,

I am trying to execute "Create Standby Using DUPLICATE" as per below document.

[oracle@sapds1dbdg1 admin]$ rman TARGET 'sys/XXXX@ds1' AUXILIARY 'sys/XXXX@ds1_dg'

Recovery Manager: Release 19.0.0.0.0 - Production on Mon Jun 7 21:22:21 2021

Version 19.3.0.0.0

Copyright (c) 1982, 2019, Oracle and/or its affiliates. All rights reserved.

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-00554: initialization of internal recovery manager package failed

RMAN-04005: error from target database:

ORA-12154: TNS:could not resolve the connect identifier specified

Here is how tnsnames.ora looks like:

[oracle@sapds1dbdg1 admin]$ more tnsnames.ora

DS1 =

(DESCRIPTION =

  (ADDRESS_LIST =

   (ADDRESS =

    (PROTOCOL = TCP)

    (HOST = sapds1dbg)