javax.mail.internet.ParseException: Expected MIME type, got ;
	at javax.mail.internet.ContentType.<init>(ContentType.java:95)
	at javax.mail.internet.MimeBodyPart.updateHeaders(MimeBodyPart.java:1322)
	at javax.mail.internet.MimeBodyPart.updateHeaders(MimeBodyPart.java:1021)
	at javax.mail.internet.MimeMultipart.updateHeaders(MimeMultipart.java:419)
	at javax.mail.internet.MimeBodyPart.updateHeaders(MimeBodyPart.java:1345)
	at javax.mail.internet.MimeMessage.updateHeaders(MimeMessage.java:2106)
	at javax.mail.internet.MimeMessage.saveChanges(MimeMessage.java:2074)
	at javax.mail.Transport.send(Transport.java:123)
	at org.jenkinsci.plugins.workflow.steps.MailStep$MailStepExecution.run(MailStep.java:113)
	at org.jenkinsci.plugins.workflow.steps.MailStep$MailStepExecution.run(MailStep.java:100)
	at org.jenkinsci.plugins.workflow.steps.AbstractSynchronousStepExecution.start(AbstractSynchronousStepExecution.java:34)
	at org.jenkinsci.plugins.workflow.cps.DSL.invokeMethod(DSL.java:136)
	at org.jenkinsci.plugins.workflow.cps.CpsScript.invokeMethod(CpsScript.java:98)
	at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.call(PogoMetaClassSite.java:45)
	at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:42)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)
	at com.cloudbees.groovy.cps.sandbox.DefaultInvoker.methodCall(DefaultInvoker.java:15)
	at WorkflowScript.run(WorkflowScript:13)
	at Unknown.Unknown(Unknown)
	at ___cps.transform___(Native Method)
	at com.cloudbees.groovy.cps.impl.ContinuationGroup.methodCall(ContinuationGroup.java:69)
	at com.cloudbees.groovy.cps.impl.FunctionCallBlock$ContinuationImpl.dispatchOrArg(FunctionCallBlock.java:106)
	at com.cloudbees.groovy.cps.impl.FunctionCallBlock$ContinuationImpl.fixArg(FunctionCallBlock.java:79)
	at sun.reflect.GeneratedMethodAccessor314.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at com.cloudbees.groovy.cps.impl.ContinuationPtr$ContinuationImpl.receive(ContinuationPtr.java:72)
	at com.cloudbees.groovy.cps.impl.CollectionLiteralBlock$ContinuationImpl.dispatch(CollectionLiteralBlock.java:55)
	at com.cloudbees.groovy.cps.impl.CollectionLiteralBlock$ContinuationImpl.item(CollectionLiteralBlock.java:45)
	at sun.reflect.GeneratedMethodAccessor319.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at com.cloudbees.groovy.cps.impl.ContinuationPtr$ContinuationImpl.receive(ContinuationPtr.java:72)
	at com.cloudbees.groovy.cps.impl.ConstantBlock.eval(ConstantBlock.java:21)
	at com.cloudbees.groovy.cps.Next.step(Next.java:58)
	at com.cloudbees.groovy.cps.Continuable.run0(Continuable.java:145)
	at org.jenkinsci.plugins.workflow.cps.CpsThread.runNextChunk(CpsThread.java:164)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.run(CpsThreadGroup.java:271)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.access$000(CpsThreadGroup.java:71)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:180)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:178)
	at org.jenkinsci.plugins.workflow.cps.CpsVmExecutorService$2.call(CpsVmExecutorService.java:47)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at hudson.remoting.SingleLaneExecutorService$1.run(SingleLaneExecutorService.java:112)
	at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)