无法获取用于连接Twitter的PIN码

Question

    library(RCurl)
    library(ROAuth)
    consumerKey = "###"
     reqURL = "https://api.twitter.com/oauth/request_token"
    accessURL = "https://api.twitter.com/oauth/access_token"
    authURL =  "https://api.twitter.com/oauth/authorize"
    consumerSecret = "####"
    accessToken = "####"
    accessTokenSecret = "####"
    twitCred <- OAuthFactory$new( consumerKey = consumerKey,
                               consumerSecret = consumerSecret,
                               requestURL = reqURL,
                               accessURL = accessURL,
                               authURL = authURL)
    twitCred$handshake()

这是我尝试将R链接到Twitter的代码。但这引发了错误：

Error in function (type, msg, asError = TRUE)  : 
  Unknown SSL protocol error in connection to api.twitter.com:443

有人可以帮我解决这个问题吗？