cannot connect to X server

[liushuping0528]

Hello, how can I solve this problem?
ExampleBrowserThreadFunc started
X11 functions dynamically loaded using dlopen/dlsym OK!

    cannot connect to X server

[liushuping0528]

if self.display:
self.client = p.connect(p.GUI)
p.configureDebugVisualizer(p.COV_ENABLE_GUI, 0, physicsClientId=self.client)

[sundyCoder]

if self.display: self.client = p.connect(p.GUI) p.configureDebugVisualizer(p.COV_ENABLE_GUI, 0, physicsClientId=self.client)

Please check the version of Pybullet.