Post Go Live issue with Docusign using node.js

Here is my issue:

• We integrated docusign in our application, server side with nodejs using this tutorial https://github.com/docusign/docusign-node-client ("OAuth JSON Web Token (JWT) Grant" section)
• We have done the "Go Live Process": our application is registered in our production account
• We have replaced the test config to the production config.
• When we try to create an envelope, we get the following error: PARTNER_AUTHENTICATION_FAILED: The specified Integrator Key was not found or is disabled. Invalid account specified for user

What am I doing wrong ?

async function docusignInit() {
    var options;
    var env = [40077,50077].indexOf(config.main.port) != -1 ? 'test' :'prod';
    if (env == "test") {
        options = {
            basePath: restApi.BasePath.DEMO,
            oAuthBasePath: oAuth.BasePath.DEMO
        }
    } else {
        options = {
            oAuthBasePath: "account.docusign.com",
           // We called https://account.docusign.com/oauth/userinfo to found the uri
            basePath:"https://eu.docusign.net/restapi/"
        }
    }
    // in production, We must do
    // var apiClient = new docusign.ApiClient(options.basePath);
    // Otherwise, we get "Error: getaddrinfo ENOTFOUND undefined undefined:443"
    var apiClient = new docusign.ApiClient(options.basePath);
    var privateKeyFile = fs.readFileSync(`./server/docusign/keys/${env}/private.PEM`);
    var res = await apiClient.requestJWTUserToken(config.docusign.integratorKey, config.docusign.userName, [oAuth.Scope.IMPERSONATION, oAuth.Scope.SIGNATURE], privateKeyFile, 3600)
    var token = res.body.access_token;
    apiClient.addDefaultHeader('Authorization', 'Bearer ' + token);
    docusign.Configuration.default.setDefaultApiClient(apiClient);
    await sendDocusign({
        userId: 1,
        firstName: 'foor',
        lastName: 'bar',
        email:'foo@bar;'
    })
}


async function sendDocusign(role) {

    var envDef = new docusign.EnvelopeDefinition();
    envDef.emailSubject = 'Please signe this';
    envDef.templateId = config.docusign.templateId;

    var role = new docusign.TemplateRole();
    role.roleName = "roleName";
    role.clientUserId = role.userId;
    role.name = role.firstName + " " + role.lastName;
    role.email = role.email;

    envDef.allowReassign = false;
    envDef.templateRoles = [role];
    envDef.status = 'sent';

    var envelopesApi = new docusign.EnvelopesApi();
    return await envelopesApi.createEnvelope(config.docusign.userAccountId, {
        'envelopeDefinition': envDef
    })
}

from Post Go Live issue with Docusign using node.js