i have tried to do this

my $apiKey = 'BITSTAMP pEF7aWa';
my $apiSecret = 'sWNuYX4QS';

my $urlcb = "https://www.bitstamp.net";
my $url = URI->new($urlcb);
my $urlpath = $url->path('/api/v2/usdt_withdrawal/');

my @Char = ('a'..'z');
my $Leng = 36;
my $RandomChar = '';
for (1..$Leng) {
$RandomChar .= $Char[int rand @Char];
}

my $timestamp = int (gettimeofday * 1000);
my $nonce = $RandomChar;

my $Query = URI->new();
$Query->query_form(
'currency' => "USDT",
'network' => "ethereum",
'address'   => "#wallet",
'amount' => "4"
);

my $API_Version = 'v2';
my $ContentType = "application/x-www-form-urlencoded";
my $signature = hmac_sha256_hex($apiKey.'POST'.$urlcb.$urlpath.$Conten
+tType.$nonce.$timestamp.$API_Version.$Query, $apiSecret);

my %payload = (
"X-Auth" => $apiKey,
"X-Auth-Signature" => $signature,
"X-Auth-Nonce" => $nonce,
"X-Auth-Timestamp" => $timestamp,
"X-Auth-Version" => $API_Version,
"Content-Type" => $ContentType
);


print $Query;
print $signature;
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but am still getting this error

i have even tried to follow the API example in other Languages https://www.bitstamp.net/api/#section/Authentication/Authentication-examples

The string you compute for your signature does not match the string from the example code.

For debugging, print out the string you compute the signature over, and compare that to the example code string.

message = 'BITSTAMP ' + api_key + \
    'POST' + \
    'www.bitstamp.net' + \
    '/api/v2/user_transactions/' + \
    '' + \
    content_type + \
    nonce + \
    timestamp + \
    'v2' + \
    payload_string
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Your code should be:

my $msg = $apiKey.'POST'.$urlcb.$urlpath.$ContentType.$nonce.$timestam
+p.$API_Version.$Query, $apiSecret;
print "Computing signature over [$msg]\n";
my $signature = hmac_sha256_hex($msg, $apiSecret);
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Then, compare the output of that part with the message as it is constructed in the documentation. There are differences between the two.

the problem still persists

Error: {"status": "error", "reason": "Invalid signature", "code": "API0005"}

my $apiKey = 'BITSTAMP p25F7aWa';
my $apiSecret = 'gisWNuYX4Q';

my $urlcb = "https://www.bitstamp.net";
my $url = URI->new($urlcb);
my $urlpath = $url->path('/api/v2/usdt_withdrawal/');

my @Char = ('a'..'z');
my $Leng = 36;
my $RandomChar = '';
for (1..$Leng) {
$RandomChar .= $Char[int rand @Char];
}

my $timestamp = int (gettimeofday * 1000);
my $nonce = $RandomChar;

my $Query = URI->new();
$Query->query_form(
'currency' => "USDT",
'network' => "ethereum",
'address'   => "Ef4cAwayizMH",
'amount' => "4"
);

my $API_Version = 'v2';
my $ContentType = "application/x-www-form-urlencoded";
my $msg = $apiKey.'POST'.$urlcb.$urlpath.$ContentType.$nonce.$timestam
+p.$API_Version.$Query, $apiSecret;
my $signature = hmac_sha256_hex($msg, $apiSecret);

my %payload = (
"X-Auth" => $apiKey,
"X-Auth-Signature" => $signature,
"X-Auth-Nonce" => $nonce,
"X-Auth-Timestamp" => $timestamp,
"X-Auth-Version" => $API_Version,
"Content-Type" => $ContentType
);

my $req = HTTP::Request->new(POST=>$url);
$req->header(%payload);
$req->content($Query);

my $resp = $ua->request($req);

if($resp->is_success){
   print $resp->content ."\n";
}
else{
  print "Error: " . $resp->content;
}
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