Java Mail not send email

Question

I'm using javax.mail-api 1.5.3 to send email. Here is my email sending code:

    Properties properties = System.getProperties();
    properties.setProperty("mail.smtp.host", host);
    properties.setProperty("mail.smtp.port", port);
    properties.setProperty("mail.user", user);
    properties.setProperty("mail.password", password);
    properties.setProperty("mail.debug", "true");
    Session mailSession = Session.getDefaultInstance(properties);
    MimeMessage mimeMessage = new MimeMessage(mailSession);
    mimeMessage.setHeader("Content-Type", "text/html; charset=UTF-8");
    mimeMessage.setFrom(new InternetAddress(from));
    mimeMessage.addRecipient(Message.RecipientType.TO, new InternetAddress(to));
    mimeMessage.setSubject(subject, "UTF-8");
    mimeMessage.setContent(body, "text/html; charset=UTF-8");
    Transport.send(mimeMessage);

But this code cause the following error.

Debug output:

DEBUG: getProvider() returning javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Oracle]
DEBUG SMTP: useEhlo true, useAuth false
DEBUG SMTP: trying to connect to host "my.smtp.host", port 25, isSSL false
220 <mail.mysite.com> <mysite>
DEBUG SMTP: connected to host "my.smtp.host", port: 25

EHLO my-pc
250-mail.mysite.com Hello [192.168.120.120]
250-SIZE
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-AUTH LOGIN
250-8BITMIME
250-BINARYMIME
250 CHUNKING
DEBUG SMTP: Found extension "SIZE", arg ""
DEBUG SMTP: Found extension "PIPELINING", arg ""
DEBUG SMTP: Found extension "DSN", arg ""
DEBUG SMTP: Found extension "ENHANCEDSTATUSCODES", arg ""
DEBUG SMTP: Found extension "AUTH", arg "LOGIN"
DEBUG SMTP: Found extension "8BITMIME", arg ""
DEBUG SMTP: Found extension "BINARYMIME", arg ""
DEBUG SMTP: Found extension "CHUNKING", arg ""
DEBUG SMTP: use8bit false
MAIL FROM:<test@mysite.com>
250 2.1.0 Sender OK
RCPT TO:<bob123456@gmail.com>
550 5.7.1 Unable to relay
DEBUG SMTP: Invalid Addresses
DEBUG SMTP:   bob123456@gmail.com
DEBUG SMTP: Sending failed because of invalid destination addresses
RSET
250 2.0.0 Resetting
DEBUG SMTP: MessagingException while sending, THROW: 
javax.mail.SendFailedException: Invalid Addresses;
  nested exception is:
    com.sun.mail.smtp.SMTPAddressFailedException: 550 5.7.1 Unable to relay

    at com.sun.mail.smtp.SMTPTransport.rcptTo(SMTPTransport.java:1950)
    at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:1195)
    at javax.mail.Transport.send0(Transport.java:254)
    at javax.mail.Transport.send(Transport.java:124)
    at org.bob.resume.service.MailService.send(MailService.java:80)
    at org.bob.resume.service.MailService.send(MailService.java:89)
    at org.bob.resume.service.MailService.send(MailService.java:95)
    at org.bob.resume.controller.AdminController.submitPersonUser(AdminController.java:267)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:776)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:705)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:868)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.bob.resume.config.BobDispatcherServletInitializer$1.doFilterInternal(BobDispatcherServletInitializer.java:126)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:85)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:619)
Caused by: com.sun.mail.smtp.SMTPAddressFailedException: 550 5.7.1 Unable to relay

    at com.sun.mail.smtp.SMTPTransport.rcptTo(SMTPTransport.java:1803)
    ... 49 more
QUIT
221 Closing connection. Good bye.

This is and strange log, destinations emails are valid but this log shows that destination address is invalid!!!!

DEBUG SMTP: Sending failed because of invalid destination addresses

Note: All emails and ips are changed for this question intentionally and they are correct.

Thanks, in advance, for your attention.

Answer 1

 550 5.7.1 Unable to relay

This says: The addresses are fine, but it's not allowed to send email from the MAIL FROM: you provided to the RCPT TO: specified in your SMTP command.

Most likely the SMTP server would like you to login (use SMTP AUTH) before you send out emails.

In order to do this you could simply try this:

Transport.send(mimeMessage, username, password);

Or if that fails setup proper SMTP AUTH:

props.put("mail.smtp.auth", "true");
Session mailSession = Session.getDefaultInstance(properties, new Authenticator() {
    public PasswordAuthentication getPasswordAuthentication() {
       //Fill in your data here.
       return new PasswordAuthentication("user", "password");
    }
});