I can’t import the deck how the immune system works by Lauren Sompayrac as I keep on getting the error “500: note has 4 fields, expected 3”
I got the deck from the reddit post How the Immune System Works" by Lauren M. Sompayrac
It looks like that’s an issue with the deck itself (if it’s this one? Reddit - Dive into anything) – reported by a number of people since the deck was shared 6 years ago. It might not work at all.
Otherwise, since that was before Anki 2.1 released, the file might not be compatible with a recent version of Anki. There is an add-on for Importing .anki (old anki 1) files that might help you. But you can’t use the add-on with a recent version of Anki, so you’ll have to “Downgrade & Quit” so you can install an older version of Anki to use it (the add-on page shows the compatible versions). And heed the author’s advice to keep your collection safe.
Perhaps start by asking yourself … is this all worth it for that deck?