The content could be displayed fragmentarily or distorted because of the incorrect resolution settings or content selection.
The content should be selected in accordance with the orientation and resolution of the screens on which it is going to be broadcast. If the vertical orientated content is loaded to the project which is supposed to be shown on the horizontal screens, it could cause the distortion of the reproduced content.
It's also important to set the correct scale in the Media Gallery layer settings. The optimal type of the scale will help you to avoid distortion. Standardly the "Outfit" scale is set in the project templates, which implements the optimal correlation of content parameters to the window of the media gallery. In case the content doesn't match the parameters of the screens, select the option "Fit", which allows you to display the content within any screens.