ServicePointManager.Expect100Continue = true;
ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;
ServicePointManager.DefaultConnectionLimit = 9999;
<pre>
OAuthTokenCredential tokenCredential = new OAuthTokenCredential(ConfigurationManager.AppSettings["PayPalClientID"].ToString(), ConfigurationManager.AppSettings["PayPalClientSecret"].ToString());
string accessToken = tokenCredential.GetAccessToken();</pre>