Couldn't "note" be "bericht", "a message"?
Bericht would translate as message. Note also translate to notie or memo.
Briefje was indicated as wrong. Nota was not one of the suggested translations of note.
De nota and Het briefje
If you choose to type "de" first, but the noun after it is incorrect, Duo will find the first possible noun for "de" rather than telling you the article is wrong. ;)