Cannot bulk load because the file could not be opened. Operating System Error Code 3

I do not know if you solved this issue, but I ran into the same issue. If the instance is local you must check the permission to access the file, but if you are accessing from your computer to a server (remote access) you have to specify the path in the server, so that means to include the file in a server directory, that solved my case.

example:

BULK INSERT Table
FROM 'C:\bulk\usuarios_prueba.csv' -- This is server path not local
WITH 
  (
     FIELDTERMINATOR =',',
     ROWTERMINATOR ='\n'
  );