Iron Golems not Spawning

Built multiple types of iron golem farms (https://www.youtube.com/watch?v=POTL0MiYqDc and https://www.youtube.com/watch?v=_DvgXuJo144). The first one worked right after it was built in a creative world. After I exited and re-entered it a few days later it stopped working. I have since rebuilt the iron farm multiple times and tried different types of farms but nothing seems to be producing iron golems. The villagers have all taken on their given trades, are sleeping, and I checked the lines of sight and they are acting the same way that they are in the video. 

      In addition, I have downloaded a world with an iron golem spawner and it is not working (the file is included, here is where I found it: https://www.planetminecraft.com/project/most-productive-iron-golem-farm-for-minecraft-1-14-over-1300-ingots-per-hour/download/worldmap/). I tried peaceful, easy and normal, but the iron golems won't spawn. I even tried making a T out of iron blocks with a carved pumpkin on the top middle but that won't make an iron golem. The only way I can get them to spawn in my world is if I use a command to drop them into the game. Please help!

Thank you!