RS if a guest is removed from a course

2016-01-23 19:57:20,289 [ajp-nio2-8036-exec-7] ERROR OLATRuntimeException - OLAT::ERROR ^%^ N36-E2 

https://xyz.olat.com/auth/1%3A1%3A0%3A0%3A0/ ^%^ Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/601.3.9 (KHTML, like Gecko) Version/9.0.2 Safari/601.3.9

**RedScreen**

<dispatchinfo>
	<componentinfo>
		<compname>link_0</compname>
		<compclass>org.olat.core.gui.components.link.Link</compclass>
		<extendedinfo>n/a</extendedinfo>
		<event>
			<class&gt;org.olat.core.gui.control.Event</class&gt;
			<command>link_0</command>
			<tostring>com:link_0,org.olat.core.gui.control.Event@be46a54a</tostring>
		</event>
	</componentinfo>
	<controllerinfo>
		<controllername>org.olat.core.gui.control.generic.modal.DialogBoxController</controllername>
		<controllername>org.olat.repository.ui.list.RepositoryEntryDetailsController</controllername>
		<controllername>org.olat.course.run.CourseRuntimeController</controllername>
		<controllername>org.olat.core.commons.fullWebApp.BaseFullWebappController</controllername>
	</controllerinfo>
</dispatchinfo>

>>> stack of 1.cause::org.olat.core.logging.OLATRuntimeException: null
-> at org.olat.core.gui.exception.ExceptionWindowController.<init>(ExceptionWindowController.java:116)
   at org.olat.core.gui.exception.MsgFactory.createMessageChiefController(MsgFactory.java:57)
   at org.olat.core.gui.exception.MsgFactory.createMessageChiefController(MsgFactory.java:46)
   at org.olat.core.gui.components.Window.dispatchRequest(Window.java:536)
   at org.olat.core.gui.components.Window.doDispatchRequest(Window.java:234)
   at org.olat.core.gui.components.AbstractComponent.dispatchRequest(AbstractComponent.java:193)
   at org.olat.dispatcher.AuthenticatedDispatcher.processValidDispatchURI(AuthenticatedDispatcher.java:245)
   at org.olat.dispatcher.AuthenticatedDispatcher.execute(AuthenticatedDispatcher.java:201)
   at org.olat.core.servlets.OpenOLATServlet.executeUserRequest(OpenOLATServlet.java:280)
   at org.olat.core.servlets.OpenOLATServlet.doGet(OpenOLATServlet.java:209)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
>>> stack of 2.cause::java.lang.NullPointerException: null
-> at javax.mail.internet.InternetAddress.checkAddress(InternetAddress.java:1147)
   at javax.mail.internet.InternetAddress.validate(InternetAddress.java:1129)
   at org.olat.core.util.mail.manager.MailManagerImpl.createAddressWithName(MailManagerImpl.java:1242)
   at org.olat.core.util.mail.manager.MailManagerImpl.createFromAddress(MailManagerImpl.java:1347)
   at org.olat.core.util.mail.manager.MailManagerImpl.saveDBMessage(MailManagerImpl.java:914)
   at org.olat.core.util.mail.manager.MailManagerImpl.sendMessage(MailManagerImpl.java:683)
   at org.olat.repository.RepositoryMailing.sendEmail(RepositoryMailing.java:146)
   at org.olat.repository.RepositoryManager.removeParticipant(RepositoryManager.java:1731)
   at org.olat.repository.RepositoryManager.leave(RepositoryManager.java:1449)
   at org.olat.repository.ui.list.RepositoryEntryDetailsController.doLeave(RepositoryEntryDetailsController.java:586)
   at org.olat.repository.ui.list.RepositoryEntryDetailsController.event(RepositoryEntryDetailsController.java:516)