Related Post Plugin – Default Thumbnail not showing

Hi. I tried your plugin a while ago in my staging site. Today I went in to install it in my live site. I noticed that the plugin has been updated and I manage to set it up again. The only thing that didn't worked was the Default Thumbnail not showing for those post that don't have a featured image set.

Example not showing default thumbnail: https://teachers.speakinglatino.com/download/possessive-and-demonstrative-adjectives-position-of-adjectives/

Example showing featured images: https://teachers.speakinglatino.com/download/google-translate-lesson-plan/