A TimThumb error has occured

The following error(s) occured:

The remote file is not a valid image. Mimetype = 'text/html' File = /var/www/html/timthumb/cache/timthumbLOWDlE

Query String : w=980&zc=1&src=http://www.campingorlandoinchianti.it//gestione/uploads/img/25266_wbhc_2017_a.jpg
TimThumb version : 2.8.13