Found Error : TNS-12560: TNS:protocol adapter error TNS-00583: Valid node checking: unable to parse configuration parameters

Recently i got error while starting an listener, Reason was i made some changes in sqlnet.ora file adding TDE wallet location, Once disable it , Able to open listener file.

TNS-12560: TNS:protocol adapter error
 TNS-00583: Valid node checking: unable to parse configuration parameters

[oracle@srv1 admin]$ cat listener.ora
# listener.ora Network Configuration File: /u01/app/oracle/product/12.1.0/dbhome_1/network/admin/listener.ora
# Generated by Oracle configuration tools.

LISTENER_STANDALONE =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = srv1.example.com)(PORT = 1521))
    )
  )

[oracle@srv1 admin]$ lsnrctl start listener_standalone

LSNRCTL for Linux: Version 12.1.0.2.0 - Production on 01-AUG-2019 14:31:47

Copyright (c) 1991, 2014, Oracle.  All rights reserved.

Starting /u01/app/oracle/product/12.1.0/dbhome_1/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 12.1.0.2.0 - Production
System parameter file is /u01/app/oracle/product/12.1.0/dbhome_1/network/admin/listener.ora
Log messages written to /u01/app/oracle/diag/tnslsnr/srv1/listener_standalone/alert/log.xml
Error listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=srv1.example.com)(PORT=1521)))
TNS-12560: TNS:protocol adapter error
TNS-00583: Valid node checking: unable to parse configuration parameters


Listener failed to start. See the error message(s) above...

[oracle@srv1 admin]$ ll
total 52
-rw-r--r--. 1 oracle oinstall  344 Jun 26 13:33 listener1906261PM3350.bak
-rw-r--r--. 1 oracle oinstall  344 Jun 26 13:34 listener1906261PM3404.bak
-rw-r--r--. 1 oracle oinstall  491 Jun 26 13:55 listener1906261PM5505.bak
-rw-r--r--. 1 oracle oinstall  491 Jun 26 13:56 listener1906261PM5616.bak
-rw-r--r--. 1 oracle oinstall  301 Jun 26 13:56 listener.ora
drwxr-xr-x. 2 oracle oinstall 4096 Jun 25 17:13 samples
-rw-r--r--. 1 oracle oinstall  373 Oct 31  2013 shrept.lst
-rw-r--r--  1 oracle oinstall  177 Aug  1 14:15 sqlnet.ora
-rw-r--r--. 1 oracle oinstall  518 Jun 26 13:33 tnsnames1906261PM3350.bak
-rw-r--r--. 1 oracle oinstall  518 Jun 26 13:34 tnsnames1906261PM3404.bak
-rw-r--r--. 1 oracle oinstall  518 Jun 26 13:55 tnsnames1906261PM5505.bak
-rw-r--r--. 1 oracle oinstall  518 Jun 26 13:56 tnsnames1906261PM5616.bak
-rw-r--r--. 1 oracle oinstall  518 Jun 26 13:41 tnsnames.ora
[oracle@srv1 admin]$ vi sqlnet.ora
[oracle@srv1 admin]$ cat sqlnet.ora
# add the following to it:
#ENCRYPTION_WALLET_LOCATION =
#(SOURCE =
#(METHOD = FILE)
#(METHOD_DATA =
#(DIRECTORY = /u01/app/oracle/product/12.1.0/dbhome_1/dbs/keystore)))
[oracle@srv1 admin]$ lsnrctl start listener_standalone

LSNRCTL for Linux: Version 12.1.0.2.0 - Production on 01-AUG-2019 14:32:55

Copyright (c) 1991, 2014, Oracle.  All rights reserved.

Starting /u01/app/oracle/product/12.1.0/dbhome_1/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 12.1.0.2.0 - Production
System parameter file is /u01/app/oracle/product/12.1.0/dbhome_1/network/admin/listener.ora
Log messages written to /u01/app/oracle/diag/tnslsnr/srv1/listener_standalone/alert/log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=srv1.example.com)(PORT=1521)))

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=srv1.example.com)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     listener_standalone
Version                   TNSLSNR for Linux: Version 12.1.0.2.0 - Production
Start Date                01-AUG-2019 14:32:55
Uptime                    0 days 0 hr. 0 min. 0 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/oracle/product/12.1.0/dbhome_1/network/admin/listener.ora
Listener Log File         /u01/app/oracle/diag/tnslsnr/srv1/listener_standalone/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=srv1.example.com)(PORT=1521)))
The listener supports no services
The command completed successfully
[oracle@srv1 admin]$ ps -ef |grep lsnr
grid      7385     1  0 Jul31 ?        00:00:02 /u01/app/12.1.0/grid/bin/tnslsnr LISTENER -no_crs_notify -inherit
grid      7397     1  0 Jul31 ?        00:00:03 /u01/app/12.1.0/grid/bin/tnslsnr LISTENER_SCAN1 -no_crs_notify -inherit
oracle   20680     1  0 14:32 ?        00:00:00 /u01/app/oracle/product/12.1.0/dbhome_1/bin/tnslsnr listener_standalone -inherit
oracle   20685  9923  0 14:33 pts/0    00:00:00 grep lsnr
[oracle@srv1 admin]$