Issue sending email from designer using smtp service

Hi
I am trying to send an email using the pub.client:smtp from my gmail but getting the below error. Can anyone suggest me If I need to do some configuration changes from the settings by configuring a new port for this or some addition extended settings are required

om.wm.app.b2b.server.ServiceException: com.sun.mail.smtp.SMTPSendFailedException: 530 5.7.0 Must issue a STARTTLS command first. y10sm4462949pgi.54 - gsmtp

com.wm.app.b2b.server.ServiceException: com.sun.mail.smtp.SMTPSendFailedException: 530 5.7.0 Must issue a STARTTLS command first. y10sm4462949pgi.54 - gsmtp

at pub.clientimpl.smtp(clientimpl.java:501)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.wm.app.b2b.server.JavaService.baseInvoke(JavaService.java:411)
at com.wm.app.b2b.server.invoke.InvokeManager.process(InvokeManager.java:739)
at com.wm.app.b2b.server.util.tspace.ReservationProcessor.process(ReservationProcessor.java:46)
at com.wm.app.b2b.server.invoke.StatisticsProcessor.process(StatisticsProcessor.java:61)
at com.wm.app.b2b.server.invoke.ServiceCompletionImpl.process(ServiceCompletionImpl.java:250)
at com.wm.app.b2b.server.invoke.ValidateProcessor.process(ValidateProcessor.java:56)
at com.wm.app.b2b.server.invoke.PipelineProcessor.process(PipelineProcessor.java:178)

Thanks & regards
Vikas

check this post:
http://techcommunity.softwareag.com/pwiki/-/wiki/Main/Using%20the%20SMTP%20Application%20to%20send%20emails