Could not connect to SMTP host: {remote-server}, port: {port}, response: -1

Question

I am trying to send mail using java mail api. But exception is come to me with above message.

Could not connect to SMTP host: {remote-server}, port: {port}, response: -1

What`s mean "response : -1"

I can`t found this code in api manual.

Answer 1

A response code of -1 means that JavaMail failed to get a valid response code from the SMTP server. You can view the relevant source here .

Most likely, you either have your properties set incorrectly or you have a networking issue such as a firewall blocking the connection.

You might try enabling debug mode ( session.setDebug(true) ). Please post your code if you need further help.