Twitter Friendship/create api asking for authentication in swift

ios

#1

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I am trying post a follow the user but am still not able to hit post api POST https://api.twitter.com/1.1/friendships/create.json?user_id=1401881&follow=true.

it is showing :

Error: Optional(Error Domain=TwitterAPIErrorDomain Code=220 “Request failed: forbidden (403)” UserInfo={NSLocalizedFailureReason=Twitter API error : Your credentials do not allow access to this resource. (code 220), TWTRNetworkingStatusCode=403, NSErrorFailingURLKey=https://api.twitter.com/1.1/friendships/create.json?user_id=12345&follow=true, NSLocalizedDescription=Request failed: forbidden (403)})
can anyone help me out for this. Thanks in advance