I am having the same issue now. When I try to go to https://github.atom.io/login I got redirected to https://github.blog/news-insights/product-news/sunsetting-atom/ That says:

January 30, 2023 Update: Update to the previous version of Atom before February 2 [...]These versions of Atom will stop working on February 2. To keep using Atom, users will need to download a previous Atom version.1.63.1 / 1.63.0

Mine is 1.60.0 x64