HI can you try editing start.php and change
$reportico->pdf_engine = "phantomjs";
$reportico->pdf_engine = "tcpdf";
Does that work ( this uses a different engine that doesnt look as good )
By default reportico uses a program called phantomjs to turn HTML into PDF ... I am aware that the some hosting providers do allow native programs to be run for security reasons and this could be the reason...
Can you tell me how you re using reportico ( e.g. standalone or is it in a framework like laravel/yii ) and which version and did you download it from the web site or use composer? Dont worry if you cant answer all these.