502 bad gateway after reboot the server? any hep

Not working

SMTP settings

smtp.eu.mailgun.org

Our servers listen on ports 25, 587, and465(SSL/TLS)

Use full email address like

 brad@guru61.com 

as the username.

“mail”: {
“from”: “noreply@guru61.com”,
“transport”: “SMTP”,
“options”: {
“host”: “smtp.eu.mailgun.org”,
“port”: 587,
“service”: “Mailgun”,
“secure”: false,
“requireTLS”: true,
“auth”: {
“user”: “postmaster@guru66.com”,
“pass”: “b20465dda274a205ea2be3a6ec83fb75-d1a07e51-b5d918a5”
}
}
},