Before sending out a real campaign, we highly recommend creating a small email list with a couple of test email addresses and send a campaign to it. This way, you can verify that sending mails, and the open & click tracking are all working correctly.
If after provisioning, you can't access it via the web it could be caused that certbot couldn't get a certificate. Make sure that the domain name you want to use has an A record that points to the server. You can let certbot retry getting a certificate by running certbot --nginx on your server.