Linux X11 security problem

Today I ran a script under linux and got such error:
Xlib: connection to ":0.0" refused by server

X11 security: the user that tries to open a window
is an other one than the one that is logged-in (even root cannot access
this). Start by removing X11 security with `xhost +`.


The solution is to execute xhost + under root user. After that, a message was displayed "access control disabled, clients can connect from any host".