Vellum has been decommissioned
After over a decade, Vellum is no longer running. All projects and their contents have been migrated to Google Drive and shared with the people who had access to them on Vellum. Full backups of everything were also made before shutting the site down, so nothing has been lost.
If you're looking for a project that used to live here, check the Google Drive folders shared with your email address, or the migration email you should have received. If you have any questions, can't find something, or need anything restored, just reach out.