xorg-server

[Tom]

>> Hi, 
>> 
>> when trying to run an X11 program, I get the following error message:
>> 
>> (putty:8198): Gtk-WARNING **: 00:06:49.190: cannot open display: :0
>> 
>> How can I fix that?
> 
> Assuming you are running Mac OS X 10.5 or later:
> 
> Check your .zprofile or .profile or .bash_profile for a line like:
> 
> DISPLAY=:0
> 
> Delete it.
> 
> The MacPorts 2.6.4 installer for macOS 11 erroneously added this line. This problem has been fixed in newer versions of the MacPorts installer but any erroneous DISPLAY line added by the 2.6.4 installer needs to be removed manually.

Now xorg-server is starting and quiting. The app does not appear.
What could be the problem?