wkhtmltoimage - trying to get thumbail from site hosted in the same ip

Question

I'm trying to get site thumbnails using wkhtmltoimage

It seems to be working except from sites that are being hosted in the same ip

This is what i get from shell when requesting a thumbnail from another site hosted to the same server:

Loading page (1/2)
QHttpNetworkConnectionChannel::_q_receiveReply() called without QHttpNetworkReply, 0 bytes on socket.
Rendering (2/2)
QPixmap: Cannot create a QPixmap when no GUI is being used   ] 25%
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPixmap: Cannot create a QPixmap when no GUI is being used
QPainter::begin: Paint device returned engine == 0, type: 2
QPainter::setRenderHint: Painter must be active to set rendering hints
QPainter::translate: Painter not active
QPainter::setPen: Painter not active
QPainter::setBrush: Painter not active
QPainter::setWorldTransform: Painter not active
QPainter::setOpacity: Painter not active
QPainter::setFont: Painter not active
Segmentation fault

Is there a way to solve this issue or i have to order a second ip for my server?