Failed to create window


running on ubuntu 18.04 Haxe 4

i just installed hashlink and compiled the hellohl example and i am getting this error when running the hello.hl file
any clue why
Failed to create window
Called from sdl.$Window.constructor (sdl/Window.hx line 66)
Called from hxd.$Window.constructor (hxd/Window.hl.hx line 42)
Called from hxd.$System.start (hxd/System.hl.hx line 101)
Called from hxd.$App.constructor (hxd/App.hx line 45)
Called from $Main.constructor (Main.hx line 1)
Called from $Main.main (Main.hx line 7)