Finally it is working. thanks for all help and pointers shared with me which helped me to learn a lot and make it work. For rest of community users (like me 🙂 ) below are the issues and resolutions.

From the Quest REST API documentation,

Anyway, I tried POSTMAN and downloaded the QUEST collection and started working on it and then came to know about above issues and corrective actions and it worked afterwards. For community users, below is the short code for authentication:

use REST::Client;
use JSON qw(decode_json);
use Data::Dumper;
my $client = REST::Client->new(host => 'https://<Your Host>:<APIPort>/
+api/v1');
$req = "authToken=<Authentication Token Value>";
$headers = {
Accept => '*/*',
'Content-Type' => 'application/x-www-form-urlencoded',
};
#Below 2 lines are to bypass the SSL verification which was also causi
+ng authentication issues.
$client->getUseragent()->ssl_opts(verify_hostname => 0);
$client->getUseragent()->ssl_opts(SSL_verify_mode => SSL_verify_NONE);
$client->POST('/security/login',$req,$headers);
print($client->responseCode());
print($client->responseContent());
exit();
[download]

#Below 2 lines are to bypass the SSL verification which was also causi
+ng authentication issues.
$client->getUseragent()->ssl_opts(verify_hostname => 0);
$client->getUseragent()->ssl_opts(SSL_verify_mode => SSL_verify_NONE);
[download]

It's dangerous not to verify the certificates, it makes a man-in-the-middle attack possible. If this is for production code, fix the cause instead of silencing the symptoms.

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]