Cannot upload featured image on blog post

Hi Support, I am trying to upload a featured image on my blog post https://steficorner.com/big-decisions-part-2/?preview=true&_thumbnail_id=2676. After selecting the image and clicking Upload, it keeps on loading. After a while, the following is displayed "Updating failed. You are probably offline." It's a small picture that in the past could be uploaded and also my internet connection is ok. Could you help me out?