POST https://xxx.xx.xx.xx/api/v2/access/token
200
62 ms
Warning: Self signed certificate
POST /api/v2/access/token HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Authorization: Basic bGJLN0dLaGNmVTM2MkxNbjpzOUtKRXR0UVBHeGIyTkxkcEpMM
+3hHbmlLN0MwaUk=
User-Agent: PostmanRuntime/7.29.0
Accept: */*
Cache-Control: no-cache
Postman-Token: 1979ab3e-0607-4544-a239-05d37cb2dd87
Host: 172.20.19.21
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Content-Length: 29
 
grant_type=client_credentials
 
HTTP/1.1 200 OK
Server: nginx
Date: Sat, 05 Mar 2022 07:31:30 GMT
Content-Type: application/json; charset=utf-8
Transfer-Encoding: chunked
Connection: keep-alive
ETag: W/"63-lVO9g4PVOvVMxmtOQ57cFQLhFck"
Strict-Transport-Security: max-age=31536000; includeSubDomains
Content-Encoding: gzip
 
{"access_token":"16f7a07cc25b2cf3618b8286180eb264744e145f","expires_in
+":3600,"token_type":"bearer"}
[download]

#!/usr/bin/perl -w
use strict;
use warnings;
use LWP::UserAgent;
my $netloc = "xxx.xx.xx.xx";
my $realm = "Realm";
my $user = "usercode";
my $pass = "passcode";
my $ua = LWP::UserAgent->new();
$ENV{PERL_LWP_SSL_VERIFY_HOSTNAME}=0;
$ua->default_header( "Authorization" => "Basic bGJLN0dLaGNmVTM2MkxNbjp
+zOUtKRXR0UVBHeGIyTkxkcEpMM3hHbmlLN0MwaUk=");
$ua->default_header( "Accept" => "*/*"  );
$ua->default_header( "Content-Type" => "application/x-www-form-urlenco
+ded");
$ua->credentials( $netloc, $realm, $user, $pass);
$ua->ssl_opts( verify_hostname => 0, SSL_verify_mode => 0x00);
my $query = "https://".$netloc."/api/v2/access/token";
my $req = HTTP::Request->new( POST => $query);
my $resp = $ua->request($req);
if ($resp->is_success) {
    my $output = $resp->decoded_content;
    print $output."\n";
}
else {
    print $resp->as_string();
}
[download]

[user@localhost wifi]$ ./wifi-api-test-token.pl
HTTP/1.1 400 Bad Request
Connection: close
Date: Sat, 05 Mar 2022 07:34:43 GMT
ETag: W/"1b-WJVp2bnCdBNm40JHvp3t41llPJs"
Server: nginx
Content-Length: 27
Content-Type: application/json; charset=utf-8
Client-Date: Sat, 05 Mar 2022 07:35:10 GMT
Client-Peer: 172.20.19.21:443
Client-Response-Num: 1
Client-SSL-Cert-Issuer: /O=Cambium Networks Ltd.
Client-SSL-Cert-Subject: /O=Cambium Networks Ltd.
Client-SSL-Cipher: ECDHE-RSA-AES128-GCM-SHA256
Client-SSL-Socket-Class: IO::Socket::SSL
Client-SSL-Version: TLSv1_2
Client-SSL-Warning: Peer certificate not verified
Strict-Transport-Security: max-age=31536000; includeSubDomains

{"error":"invalid_request"}
[download]

OK guys, it's ok I figured it out through viewing several other script examples. So this is my final script.

#!/usr/bin/perl -w
use strict;
use warnings;
use LWP::UserAgent;
my $netloc = "xxx.xx.xx.xx";
my $realm = "Realm";
my $user = "usercode";
my $pass = "passcode";
my $ua = LWP::UserAgent->new();
$ENV{PERL_LWP_SSL_VERIFY_HOSTNAME}=0;
$ua->default_header( "Authorization" => "Basic bGJLN0dLaGNmVTM2MkxNbjp
+zOUtKRXR0UVBHeGIyTkxkcEpMM3hHbmlLN0MwaUk=");
$ua->default_header( "Accept" => "*/*"  );
$ua->default_header( "Content-Type" => "application/x-www-form-urlenco
+ded");
$ua->credentials( $netloc, $realm, $user, $pass);
$ua->ssl_opts( verify_hostname => 0, SSL_verify_mode => 0x00);
my $url = "https://".$netloc."/api/v2/access/token";
my $resp = $ua->post($url, Content => ['grant_type' =>  "client_creden
+tials"]);
if ($resp->is_success) {
    my $output = $resp->decoded_content;
    print $output."\n";
}
else {
    print $resp->as_string();
}
[download]

And I now get the following output.

{"access_token":"ea1dda77710f64b0db328415427a1463e74ea204","expires_in
+":3600,"token_type":"bearer"}
[download]

Thank you for taking time and steering me in the right direction. That postman console really helped me a lot. Thank you very much.