I deployed AEM 6.0 war (SP1) on JBoss 7.1 version. When i'm running "Request for Activation" (or any other custom java program for sending emails) workflow on any page, it give me the below error and it doesn't send email. I've configured SMTP correctly. Also, i tried to run a custom java program to send emails, it's throwing the same error. I was able to send emails with the same custom java program when i run that from eclipse.
javax.mail.MessagingException: SMTP can only send RFC822 messages at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:1080) at com.hds.cq.obc.CustomSendEmailProcess.sendEmail(CustomSendEmailProcess.java:119) at com.hds.cq.obc.CustomSendEmailProcess.execute(CustomSendEmailProcess.java:67) at com.day.cq.workflow.compatibility.CQWorkflowProcessRunner.execute(CQWorkflowProcessRunner.java:93) at com.adobe.granite.workflow.core.job.HandlerBase.executeProcess(HandlerBase.java:208) at com.adobe.granite.workflow.core.job.JobHandler.process(JobHandler.java:140) at org.apache.sling.event.jobs.JobUtil$1.run(JobUtil.java:365) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:744)