Unable to use images as Thumbnails

Recently my website was working just fine, and I always used a plugin to generate thumbnails, now even with old images and posts thumbnails are no longer used in website, and 3 mb size image to stream each time and load is to much. https://s3.amazonaws.com/satisfaction-production/s3_images/275132/wp-error_inline.jpg Is just simply gone. Now I am not crazy and I didn’t changed any other settings.