Same issue with e.g. devtools:
> devtools::install_github("r-lib/devtools")
Error in stop(github_error(req)) :
This endpoint requires you to be authenticated. (401)
> traceback()
10: stop(github_error(req))
9: github_response(req)
8: github_POST("graphql", body = jsonlite::toJSON(auto_unbox = TRUE,
list(query = query, variables = list(org = username, repo = repo,
ref = ref))))
7: github_sha(username = remote$username, repo = remote$repo, host = remote$host,
ref = remote$ref, pat = remote$auth_token)
6: remote_sha.github_remote(remote)
5: remote_sha(remote)
4: FUN(X[[i]], ...)
3: vapply(remotes, install_remote, ..., FUN.VALUE = logical(1))
2: install_remotes(remotes, quiet = quiet, ...)
1: devtools::install_github("r-lib/devtools")
It's weird, 'cause I have previously installed on this server with no issues...