MoTTY X11 proxy: No authorisation provided java.lang.NoClassDefFoundError: Could not initialize class sun.awt.X11.XToolkit - is not correctly set, is not correctly set, - is missing or not configured, is missing or not configured, - or is not being used or trusted. or is not being used or trusted. is not correctly set, is missing or not configured, or is not being used or trusted. Step 1: Confirm is installed

If it returns nothing: Step 2: In session config: - Go to Advanced SSH settings Go to Advanced SSH settings - ✅ Ensure “X11 forwarding” is checked ✅ Ensure “X11 forwarding” is checked Go to Advanced SSH settings

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which xauth

sudo yum install xauth # RHEL/CentOS
# or
sudo apt install xauth # Debian/Ubuntusudo yum install xauth # RHEL/CentOS
# or
sudo apt install xauth # Debian/Ubuntu

✅ Ensure “X11 forwarding” is checked Step 3: Verify environment variable After login, run: Expected output:

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echo $DISPLAY

localhost:10.0

Step 4: Generate entries If it returns nothing or errors: Then re-check:

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xauth list

xauth generate $DISPLAY . trusted

xauth list

Step 5: Test with lightweight GUI app If opens a window on your Windows desktop → SUCCESS ✅ Step  6 : Check output of below command

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xclock

echo $DISPLAY
xauth list

export DISPLAY=localhost:10.0
xclock

If above one is failed Step 7: Install Re-run the test

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sudo yum install xorg-x11-apps -y

xclock