Small hint for people who are still using Ubuntu 21.04. This was released on April 22, 2021, as you can read here. According to this page, support expires in January 2022 – 9too4linux.com has it a bit more precise in this article: the support end date is January 20, 2022. And Ubuntu 21.10 is also only supported until July 2022. Only Ubuntu 22.04 is supported until April 2027.