NASA changed the file transfer protocol, a system for browsing and retrieving data, now in use on the NASA Sea Level Portal. (For example, this applies to those who want to access global mean sea level data on this page.) The agency retired the current FTP service, available on PO.DAAC, on June 3, 2019, and is recommending that users switch to authenticated HTTPS. This will require creating a NASA Earthdata login profile. For help with HTTPS: https://podaac-tools.jpl.nasa.gov/drive/.