A TimThumb error has occured

The following error(s) occured:

The remote file is not a valid image. Mimetype = ''/var/www/vhosts/meteoindiretta.it/httpdocs/cache_webcam/timthumbyumY6N

Query String : src=http%3A%2F%2Fwww.vialattea.it%2FData%2Fvialattea_it%2FWebcam%2Ftrebialsmonte1.jpg&w=630
TimThumb version : 2.8.11