URLSession: Operation not permitted

I'm trying to do a simple POST request in Swift in my Safari Extension, but there is no way that it works.

Example code:

let url = URL(string: "https://136.243.65.157")
  let task = URLSession.shared.dataTask(with: url! as URL) { data, response, error in
    guard let data = data, error == nil else { return }
    print(NSString(data: data, encoding: String.Encoding.utf8.rawValue))
  }
  task.resume()

I get:

2019-10-19 22:03:14.430621+0200 TrashMail.com Extension[16213:361162] [] nw_socket_connect [C2:3] connectx(12 (guarded), [srcif=0, srcaddr=, dstaddr=136.243.65.157:443], SAE_ASSOCID_ANY, 0, NULL, 0, NULL, SAE_CONNID_ANY) failed: [1: Operation not permitted]
2019-10-19 22:03:14.430772+0200 TrashMail.com Extension[16213:361162] [] nw_socket_connect [C2:3] connectx failed (fd 12) [1: Operation not permitted]
2019-10-19 22:03:14.430851+0200 TrashMail.com Extension[16213:361162] [] nw_socket_connect connectx failed [1: Operation not permitted]
2019-10-19 22:03:14.431318+0200 TrashMail.com Extension[16213:361162] Connection 2: received failure notification
2019-10-19 22:03:14.431363+0200 TrashMail.com Extension[16213:361162] Connection 2: failed to connect 1:1, reason -1
2019-10-19 22:03:14.431388+0200 TrashMail.com Extension[16213:361162] Connection 2: encountered error(1:1)
2019-10-19 22:03:14.432825+0200 TrashMail.com Extension[16213:361162] Task <34726962-7BF0-4ED5-8DD2-32E4A4DDD1B3>.<2> HTTP load failed, 0/0 bytes (error code: 1 [1:1])
2019-10-19 22:03:14.433103+0200 TrashMail.com Extension[16213:361213] Task <34726962-7BF0-4ED5-8DD2-32E4A4DDD1B3>.<2> finished with error [1] Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted" UserInfo={_kCFStreamErrorCodeKey=1, _kCFStreamErrorDomainKey=1}

Is it possible that I have to do this in JavaScript instead Swift4?