Since the release of new Google Sites in 2016, Google has been planning to retire classic Google Sites and replace it with new Google Sites. Google announced their timeline for doing so in August 2020. Changes began on May 15, 2021, with the end of classic Sites creation. Now, new Google websites can only be created in new Sites. For a detailed timeline for ITS and Google retirement plans, refer to Classic Google Sites Retirement Timeline.
New Google Sites
ITS highly encourages you to convert your classic Google Sites to new Sites as soon as possible to avoid data loss in 2022/2023.
Caution: Key classic Google Sites features and functionality are still missing in new Google Sites. As a result, the conversion process is not one-to-one, and it will likely break parts of your site. Until Google brings these key features over to new Sites, you will need to adjust your sites accordingly post-conversion. Visit the Google Sites Help Center to learn more about what to expect when you convert a classic Site to a new Site.