qt.qpa.xcb: could not connect to display

[ghost]

While I am trying to visualize 3D point clouds with 3D boxes, I am getting the below error message.

Got keys from plugin meta data ("xcb")
QFactoryLoader::QFactoryLoader() checking directory path "/usr/bin/platforms" ...
loaded library "/root/venv/lib/python3.8/site-packages/cv2/qt/plugins/platforms/libqxcb.so"
qt.qpa.xcb: could not connect to display :1
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "/root/venv/lib/python3.8/site-packages/cv2/qt/plugins" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: xcb.

Aborted (core dumped)

The export command used to change the display still shows the above error with the below connection refused error.

qt.qpa.xcb: could not connect to display :1
qt.qpa.xcb: could not connect to display :0

Machine: ubuntu 22.04