Server Manager can't be stopped via "windchill stop" command in Windchill PDMLink

Exception in thread "main" wt.util.WTRemoteException: Unable to stop server manager; nested exception is:
wt.util.WTRemoteException: Unable to ping server manager; nested exception is:
wt.util.WTRemoteException: Unable to locate server manager; nested exception is:
wt.util.WTRemoteException: Unable to locate server manager's registry; nested exception is:
java.lang.RuntimeException: java.awt.HeadlessException: 
No X11 DISPLAY variable was set, but this program performed an operation which requires it.
at com.ptc.net.auth.NetAuthenticator.invokeGuiAndWait(NetAuthenticator.java:194)
at com.ptc.net.auth.NetAuthenticator.getPasswordAuthentication(NetAuthenticator.java:177)
at java.base/java.net.Authenticator.requestPasswordAuthenticationInstance(Authenticator.java:461)
at java.base/java.net.Authenticator.requestPasswordAuthentication(Authenticator.java:412)
at java.base/sun.net.www.protocol.http.HttpURLConnection$1.run(HttpURLConnection.java:455)
at java.base/sun.net.www.protocol.http.HttpURLConnection$1.run(HttpURLConnection.java:450)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/sun.net.www.protocol.http.HttpURLConnection.privilegedRequestPasswordAuthentication(HttpURLConnection.java:449)
at java.base/sun.net.www.protocol.http.HttpURLConnection.getServerAuthentication(HttpURLConnection.java:2513)
at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1766)
at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1520)
at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:250)
at wt.util.WTContext.getResourceAsStream(WTContext.java:3568)
at wt.util.WTContext.getServerResourceAsStream(WTContext.java:3711)
at wt.util.WTProperties.getServerProperties(WTProperties.java:960)
at wt.manager.RemoteServerManager.getRegistry(RemoteServerManager.java:673)
at wt.manager.RemoteServerManager.acquireServerManager(RemoteServerManager.java:537)
at wt.manager.RemoteServerManager.getServerManager(RemoteServerManager.java:516)
at wt.manager.RemoteServerManager.remoteInvoke(RemoteServerManager.java:452)
at wt.manager.RemoteServerManager.ping(RemoteServerManager.java:379)
at wt.manager.RemoteServerManager.stop(RemoteServerManager.java:401)
at wt.manager.RemoteServerManager.mainInternal(RemoteServerManager.java:804)
at wt.manager.RemoteServerManager.main(RemoteServerManager.java:779)
Caused by: java.awt.HeadlessException: 
No X11 DISPLAY variable was set, but this program performed an operation which requires it.
at java.desktop/java.awt.GraphicsEnvironment.checkHeadless(GraphicsEnvironment.java:208)
at java.desktop/java.awt.Window.<init>(Window.java:548)
at java.desktop/java.awt.Frame.<init>(Frame.java:423)
at java.desktop/java.awt.Frame.<init>(Frame.java:388)
at java.desktop/javax.swing.SwingUtilities$SharedOwnerFrame.<init>(SwingUtilities.java:1919)
at java.desktop/javax.swing.SwingUtilities.getSharedOwnerFrame(SwingUtilities.java:1995)
at java.desktop/javax.swing.JOptionPane.getRootFrame(JOptionPane.java:1689)
at java.desktop/javax.swing.JOptionPane.getWindowForComponent(JOptionPane.java:1630)
at java.desktop/javax.swing.JOptionPane.createDialog(JOptionPane.java:961)
at java.desktop/javax.swing.JOptionPane.createDialog(JOptionPane.java:923)
at com.ptc.net.auth.NetAuthenticator$LoginDialogRunner.run(NetAuthenticator.java:420)
at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:303)
at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:770)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:740)
at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)