A TimThumb error has occured

The following error(s) occured:

The remote file is not a valid image. Mimetype = ''/var/www/vhosts/loromeij.nl/httpdocs/includes/cache/timthumbOFJ03t

Query String : zc=3&w=600&h=600&src=https://www.bandwerkplus.nl/klanten/www.loromeij.nl/uploads/producten/detail/434.jpg
TimThumb version : 2.8.14