I know others have had seen and had problems with the auto fill function on the pitcher. I also have had difficulties and spent time looking at what may be creating the problem. First follow the recommendations in this link as it may be a more simple issue however these steps did not solve my issue: https://www.samsung.com/us/support/troubleshooting/TSG01201488/
Here are steps to follow to that seems to work:
1) Open up refrigerator settings on the family hub screen and look at the icon at top that gives current status of water pitcher.
2) If it says pitcher is full however the pitcher is empty open up the right side door and pull out the pitcher. Look at the icon on the screen now. It should indicate the pitcher is not in place or missing.
3) slide the pitcher into place very slow - do not just push it into the shelf. While pushing the pitcher in watch the icon an at some point while the pitch is still not full in the icon should change to filling pitcher.
4) Keep slowly pushing until on shelf and if the icon says filling pitcher close door and the pitcher will begin filling
5) Here is what I believe is happen: The white cover on the pitcher has a small metal piece molded into the lid you can see if you take it off and turn it over. When the pitcher is put in place this is what's senses if it is in place or not. There is also switch that is inside the cavity on the refrigerator where the pitcher is placed. If you reach your hand in you can push this switch. Its looks like a white plastic square and should click when pushed in and automatically pop out when you remove your hand from pushing. If the pitcher is pushed into far this switch is pushed closes and the refrigerator thinks the pitcher is full.
5) Solution with the right door open slowly pull the pitcher out an the icon should go back to filling. You will need to make sure when the pitcher is put in place it is pull back to as far as you can on the shelf. Close the door and pitcher will start filling in about 10 seconds.
Let me know if you have any luck...