ConfigTool: Can't connect to X11 window server using ':0.0' as the value of the DISPLAY variable.

We have encountered below error message while trying to launch the ConfigTool using the PuTTY. Our environment is SAP NetWeaver 7.0 (very old!) with HP-UX operating system.

java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:324)
        at com.sap.engine.offline.OfflineToolStart.main(OfflineToolStart.java:81)
Caused by: java.lang.InternalError: Can't connect to X11 window server using ':0.0' as the value of the DISPLAY variable.
        at sun.awt.X11GraphicsEnvironment.initDisplay(Native Method)
        at sun.awt.X11GraphicsEnvironment.[clinit](X11GraphicsEnvironment.java:139)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:141)
        at java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment(GraphicsEnvironment.java:62)
        at java.awt.Window.init(Window.java:231)
        at java.awt.Window.[init](Window.java:275)
        at java.awt.Frame.[init](Frame.java:401)
        at javax.swing.JFrame.[init](JFrame.java:198)
        at com.sap.engine.configtool.visual.ConfigToolView.[init](ConfigToolView.java:77)
        at com.sap.engine.configtool.visual.ConfigTool.[init](ConfigTool.java:69)
        at com.sap.engine.configtool.visual.ConfigTool.main(ConfigTool.java:961)
        ... 5 more

Solution

We are not going to write the steps here, because someone has written it very well. So, you guys can follow the how-to steps with this URL, https://blogs.sap.com/2018/12/23/enabling-x11-forwarding-on-linux/

Note: We are using MobaXterm.