I tried to send a self generated mobi file to kindle through mailgun. I tried lots of times, below are the logs for the message status
"delivery-status": {
"tls": false,
"mx-host": "",
"code": 499,
"description": null,
"session-seconds": 80.14214205741882,
"retry-seconds": 600,
"message": "Unable to connect to MX servers: [retail-smtp-in.amazon.com]",
"certificate-verified": false
},
I don't know why it shows unable to connect to MX servers. I guess it's amazon side problem cause when I send file to gmail account, it did succeed.
PS: I did set up my email address in the amazon setting.