A TimThumb error has occured

The following error(s) occured:

The remote file is not a valid image. Mimetype = ''/www/wwwroot/zs/wp-content/themes/Hsprothemes/cache/timthumbhMzRBE

Query String : h=295&src=https%3A%2F%2Fnb-bd.com%2Fwp-content%2Fuploads%2F2021%2F07%2Ftimthumb.png&w=270
TimThumb version : 2.8.13