com.sun.mail.util.MailConnectException：无法连接到主机，端口：smtp.gmail.com，587； 超时-1

Question

I had implemented the ability to send email to Java. However, from the moment I get the following error:

DEBUG SMTP: need username and password for authentication
DEBUG SMTP: protocolConnect returning false, host=smtp.gmail.com, user=USERNAME, password=<null>
DEBUG SMTP: useEhlo true, useAuth true
DEBUG SMTP: trying to connect to host "smtp.gmail.com", port 587, isSSL true
com.sun.mail.util.MailConnectException: Couldn't connect to host, port: smtp.gmail.com, 587; timeout -1;
  nested exception is:
    java.net.ConnectException: Connection refused: connect

I think my code is not wrong. Because my code works well on my two colleagues' PC. (telnet smtp.gmail.com 587) command works well.

Help me please. I could not do anything for a few days because of this.

I am a beginner and I would appreciate it if you could let me know.

Answer 1

According to this :

"Because my code works well on my two colleagues' PC. (telnet smtp.gmail.com 587) command works well"

i assume that you already authorize access through less secure app in the gmail account you're using, and the problem is related to your own computer.

Did you check your firewall or antivirus rules ?