Microsoft ファイルのホスティングおよび同期サービス。
Hello. Thanks for sharing your concern. It sounds like your OneDrive isn’t syncing because your sign-in has expired. Are you signed in with your current Microsoft 365 account in both Office and OneDrive? Try signing out and back in to refresh your credentials. Open Excel, go to File, then Account, sign out, close the app, reopen it, and sign in again. This should let you save, upload, and share your files normally. Please let me know how it goes.