Package check result: ERROR

Check: CRAN incoming feasibility, Result: NOTE
  Maintainer: ‘Gregoire Thomas <gregoire.thomas@SQU4RE.com>’
  
  Found the following (possibly) invalid URLs:
    URL: https://www.SQU4RE.com
      From: inst/doc/D4TAlink_basics.html
      Status: 403
      Message: Forbidden
    URL: https://www.d4ta.link
      From: inst/doc/D4TAlink_basics.html
      Status: 403
      Message: Forbidden
    URL: https://www.d4ta.link/
      From: DESCRIPTION
            inst/doc/D4TAlink_basics.html
      Status: 403
      Message: Forbidden

Check: tests, Result: ERROR
    Running ‘testthat.R’ [0s/0s]
  Running the tests in ‘tests/testthat.R’ failed.
  Complete output:
    > library(testthat)
    > library(usethis)
    Error in library(usethis) : there is no package called 'usethis'
    Execution halted