404 error connecting R to via Sparklyr with livy

Question

I am trying to connect our local machine to Spark with livy method.

We tried with a couple of users, but we get this error:

library(sparklyr)
sc <- spark_connect(master = "link/to/spark/via/livy",
                    version = "2.4",
                    method = "livy",
                      config = 
                        livy_config(
                                    username = 'user',
                                     password = "pwd"))
sc

We tried using CURL and the exit status was positive, so I do not get why this is not working, giving 404.

Error in livy_validate_master(master, config) : Failed to connect to Livy service at link/to/spark/via/livy. Failed to retrieve livy session (Client error: (404) Not Found):

Note: there is the tag RStudio because we used the procedure of RStudio -whom put out the code above.

Thanks in advance.