我在嘗試從 DocuSign 檢索 JWT 令牌時遇到問題，到目前為止，這是我已完成的代碼片段（使用 DEVELOPER SANDBOX 帳戶）：// Developer exmple$header = [    'typ' => 'JWT',    'alg' => 'RS256',];$time = time();$body = [    // Integration key provded by DocuSign at Admin > API and Keys > Apps.    'iss' => '[Integration key]',    // User ID provded by DocuSign at Admin > API and Keys.    'sub' => '[User ID]',    'iat' => $time,    'exp' => strtotime( '+45 minutes', $time ),    'aud' => 'account-d.docusign.com',    'scope' => 'signature impersonation',];// RSA Private key provided by DocuSign// When integration APP was created$rsa_key = '-----BEGIN RSA PRIVATE KEY----- [.........]';// Base64 + URL Encoding$header = urlencode( base64_encode( json_encode( $header ) ) );$body = urlencode( base64_encode( json_encode( $body ) ) );// JWT signature created using Firebase\JWT\JWT package$signature = JWT::encode(    $header . '.' . $body,    $rsa_key,    'RS256');// Get request using Curl (10quality/php-curl package)$response = curl_request(    'https://account-d.docusign.com/oauth/token',    'POST',    [        'grant_type' => 'urn:ietf:params:oauth:grant-type:jwt-bearer',        'assertion' => $header . '.' . $body . '.' . $signature,    ]);// Process responseif ( $response ) {    $response = json_decode( $response );    if ( isset( $response->error ) )        throw new Exception( 'DocuSign error: ' . $response->error );    var_dump( $response );}這是我遵循的指南： https: //developers.docusign.com/esign-rest-api/guides/authentication/oauth2-jsonwebtoken根據本指南，拋出的錯誤表明 JWT 未正確創建，盡管我已多次檢查我的代碼并且它遵循指南中描述的所有內容。我有點卡住了，我對我的代碼有什么問題一無所知，我什至做了逆向工程來驗證編碼是否正確。有沒有人以前使用過 DocuSign JWT 或者知道我可能做錯了什么？