Paypal SDK problems - asp.net

Question

Goodmornig,
I have some problems with the integration of SDK paypal, I have the IPN that works nice, now I was trying to do the first request, instead of the form client side, the call server side, to be more safe.
I have put in my bin folder Paypal.dll and Newtonsoft.Json.dll then I have configurated the web.config
This is what I have read when I downloaded the Paypal nuget from Visual.
ATTENTION: This package replaces the RestApiSDK package (https://www.nuget.org/packages/restapisdk). You do not need to include the RestApiSdk package in your project if you are using this, the PayPal .NET SDK, package.
The PayPal REST API uses HTTP verbs and a RESTful endpoint structure. OAuth2.0 is used as the API Authorization framework. Request and response payloads are formatted as JSON.
I usually dont use editor, I have downloaded Visual just to get out these dll.
Then I have copied them inside my Web ASP.NET application.
<configSections>
<section name="paypal" type="PayPal.SDKConfigHandler, PayPal" />
</configSections>
<!-- PayPal SDK settings -->
<paypal>
<settings>
<add name="mode" value="live" />
<add name="connectionTimeout" value="360000"/>
<add name="requestRetries" value="1"/>
<add name="clientId" value="xxx" />
<add name="clientSecret" value="yyy" />
</settings>
</paypal>
And then I have translated the c#.net script sample to vb.net, this is the code
<%# Page Language="VB" Debug="true" aspcompat=true%>
<%# Import Namespace="MySql.Data.MySqlClient" %>
<%# Import Namespace="PayPal.Api" %>
<%
' Initialize an APIContext object with a fresh access token.
' The config will be populated with values set in the Web.config file.
Dim config = ConfigManager.Instance.GetProperties()
Dim accessToken = New OAuthTokenCredential(config).GetAccessToken()
Dim apiContext = New APIContext(accessToken)
Dim abc = Payment.Get(apiContext, "6N135681R73257100")
%>
I have put the ID of the transaction and I have this kind of error
PayPal.HttpException: The remote server returned an error: (404) Not Found.
If I try to do a payment so to do like this
<%# Page Language="VB" Debug="true" aspcompat=true%>
<%# Import Namespace="MySql.Data.MySqlClient" %>
<%# Import Namespace="PayPal.Api" %>
<%
' Initialize an APIContext object with a fresh access token.
' The config will be populated with values set in the Web.config file.
Dim config = ConfigManager.Instance.GetProperties()
Dim accessToken = New OAuthTokenCredential(config).GetAccessToken()
Dim apiContext = New APIContext(accessToken)
' Initialize Payout object
Dim payout = New Payout() With { _
.sender_batch_header = New PayoutSenderBatchHeader() With { _
.sender_batch_id = "batch_" + System.Guid.NewGuid().ToString().Substring(0, 8), _
.email_subject = "You have a payment" _
}, _
.items = New List(Of PayoutItem)({ _
New PayoutItem() With { _
.recipient_type = PayoutRecipientType.EMAIL, _
.amount = New Currency() With { _
.value = "0.99", _
.currency = "USD" _
}, _
.receiver = "shirt-supplier-one#mail.com", _
.note = "Thank you.", _
.sender_item_id = "item_1" _
}, _
New PayoutItem() With { _
.recipient_type = PayoutRecipientType.EMAIL, _
.amount = New Currency() With { _
.value = "0.90", _
.currency = "USD" _
}, _
.receiver = "shirt-supplier-two#mail.com", _
.note = "Thank you.", _
.sender_item_id = "item_2" _
}, _
New PayoutItem() With { _
.recipient_type = PayoutRecipientType.EMAIL, _
.amount = New Currency() With { _
.value = "2.00", _
.currency = "USD" _
}, _
.receiver = "shirt-supplier-three#mail.com", _
.note = "Thank you.", _
.sender_item_id = "item_3" _
} _
}) _
}
' Create the payout
Dim createdPayout = payout.Create(apiContext, False)
%>
I have this kind of error, Did I forgot to copy inside my project anything? How could I fix it? Thank you very much
PayPal.HttpException: The remote server returned an error: (403) Forbidden.