NodeJS https request: Hostname/IP doesn't match certificate's altnames

I am currently trying to make a request from my node server to the onasignal REST api. My sites' got https thanks to certbot but on every call I make to their api I got the following error:

{ Error: Hostname/IP doesn't match certificate's altnames: "Host:
localhost. is not in the cert's altnames: DNS:beswapp.io, DNS:www.beswapp.io"
at Object.checkServerIdentity (tls.js:199:17)
at TLSSocket.<anonymous> (_tls_wrap.js:1068:29)
at emitNone (events.js:86:13)
at TLSSocket.emit (events.js:185:7)
at TLSSocket._finishInit (_tls_wrap.js:586:8)
at TLSWrap.ssl.onhandshakedone (_tls_wrap.js:416:38)
reason: 'Host: localhost. is not in the cert\'s altnames: 
DNS:beswapp.io, DNS:www.beswapp.io',
host: 'localhost',
cert: 
{ subject: { CN: 'beswapp.io' },
 issuer: 
  { C: 'US',
    O: 'Let\'s Encrypt',
    CN: 'Let\'s Encrypt Authority X3' },
 subjectaltname: 'DNS:domain.com, DNS:www.domain.com',
 infoAccess: { 'OCSP - URI': [Object], 'CA Issuers - URI': [Object] }

I can't figure out how and why my request's hostname is resolved as 'localhost' since I am not running anything on the same machine (client website => my node api => onesignal's api) Here is my code that makes the request:

private get CreateNotificationOptions(): RequestOptions {
    return {
        host: 'onesignal.com',
        hostname: 'domain.com',
        port: 443,
        path: '/api/v1/notifications',
        method: 'POST',
        headers: this.Headers,
        rejectUnauthorized: false
    };
}

sendNotification(data: any): Promise<any> {
    console.log('in send notification');
    return new Promise<any>((resolve, reject) => {
        const req = https.request(this.CreateNotificationOptions, res => {
            res.on('data', data => {
                resolve(data);
            });
        });

        req.on('error', err => reject(err));

        req.write(JSON.stringify(data));
        req.end();
    });
}

(I recently added the hostname and rejectUnauthorized: false but not any luck) I am using Nginx as a proxy so nginx is doing all the https config job. Any idea ?

via achauchet