Error sending Email, not sure whats wrong

Using 7.9.1.

Just trying to send an email that works for one of my users, but not for another. This is the error

Traceback (most recent call last):
  File "<event:actionPerformed>", line 101, in longProcess
	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.newGatewayException(GatewayInterface.java:329)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendMessage(GatewayInterface.java:303)

	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendEmail(GatewayInterface.java:625)

	at com.inductiveautomation.factorypmi.application.script.builtin.ClientNetUtilities._sendEmail(ClientNetUtilities.java:109)

	at com.inductiveautomation.ignition.common.script.builtin.AbstractNetUtilities.sendEmail(AbstractNetUtilities.java:147)

	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

	at java.lang.reflect.Method.invoke(Unknown Source)


com.inductiveautomation.ignition.client.gateway_interface.GatewayException: com.inductiveautomation.ignition.client.gateway_interface.GatewayException: Error sending email.

	at org.python.core.Py.JavaError(Py.java:495)
	at com.inductiveautomation.factorypmi.application.script.builtin.ClientNetUtilities._sendEmail(ClientNetUtilities.java:112)
	at com.inductiveautomation.ignition.common.script.builtin.AbstractNetUtilities.sendEmail(AbstractNetUtilities.java:147)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.python.core.PyReflectedFunction.__call__(PyReflectedFunction.java:186)
	at com.inductiveautomation.ignition.common.script.ScriptManager$ReflectedInstanceFunction.__call__(ScriptManager.java:435)
	at org.python.core.PyObject.__call__(PyObject.java:357)
	at org.python.core.PyObject.__call__(PyObject.java:361)
	at org.python.pycode._pyx239.longProcess$1(<event:actionPerformed>:112)
	at org.python.pycode._pyx239.call_function(<event:actionPerformed>)
	at org.python.core.PyTableCode.call(PyTableCode.java:165)
	at org.python.core.PyBaseCode.call(PyBaseCode.java:301)
	at org.python.core.PyFunction.function___call__(PyFunction.java:376)
	at org.python.core.PyFunction.__call__(PyFunction.java:371)
	at org.python.core.PyFunction.__call__(PyFunction.java:361)
	at org.python.core.PyFunction.__call__(PyFunction.java:356)
	at com.inductiveautomation.ignition.common.script.ScriptManager.runFunction(ScriptManager.java:660)
	at com.inductiveautomation.factorypmi.application.script.builtin.ClientSystemUtilities$4.run(ClientSystemUtilities.java:390)
	at java.lang.Thread.run(Unknown Source)
Caused by: com.inductiveautomation.ignition.client.gateway_interface.GatewayException: Error sending email.
	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.newGatewayException(GatewayInterface.java:329)
	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendMessage(GatewayInterface.java:303)
	at com.inductiveautomation.ignition.client.gateway_interface.GatewayInterface.sendEmail(GatewayInterface.java:625)
	at com.inductiveautomation.factorypmi.application.script.builtin.ClientNetUtilities._sendEmail(ClientNetUtilities.java:109)
	... 20 more
Caused by: javax.mail.AuthenticationFailedException: 535 5.7.0 authentication failed

	at com.sun.mail.smtp.SMTPTransport$Authenticator.authenticate(SMTPTransport.java:892)
	at com.sun.mail.smtp.SMTPTransport.authenticate(SMTPTransport.java:814)
	at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:728)
	at javax.mail.Service.connect(Service.java:386)
	at javax.mail.Service.connect(Service.java:245)
	at javax.mail.Service.connect(Service.java:194)
	at javax.mail.Transport.send0(Transport.java:253)
	at javax.mail.Transport.send(Transport.java:124)
	at com.inductiveautomation.ignition.gateway.script.GatewayNetUtilities.sendEmail(GatewayNetUtilities.java:195)
	at com.inductiveautomation.ignition.gateway.servlets.Gateway._sendEmail(Gateway.java:1079)
	at com.inductiveautomation.ignition.gateway.servlets.Gateway.doPost(Gateway.java:440)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
	at com.inductiveautomation.ignition.gateway.bootstrap.MapServlet.service(MapServlet.java:85)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:837)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:583)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:226)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1160)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:511)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1092)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at org.eclipse.jetty.server.handler.HandlerList.handle(HandlerList.java:52)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134)
	at org.eclipse.jetty.server.Server.handle(Server.java:518)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:308)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:244)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:273)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:95)
	at org.eclipse.jetty.io.SelectChannelEndPoint$2.run(SelectChannelEndPoint.java:93)
	at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.produceAndRun(ExecuteProduceConsume.java:246)
	at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.run(ExecuteProduceConsume.java:156)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:654)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:572)
	at java.lang.Thread.run(null)

Ignition v7.9.1 (b2017012511)
Java: Oracle Corporation 1.8.0_144

I can’t tell whats going wrong. Thoughts?

This is the relevant line. The SMTP server you're sending to didn't like the auth. Unfortunately, we don't get any more information back than that.