@NobbZ Many apologies I solved it , at the line

{:ok, conn, request_ref} = Mint.HTTP1.request(conn, "POST", "/default/en_US/sms_info.html&line=1&action=#{action}&telnum=#{telnum}&smscontent=#{smscontent}&smskey=1162480578",
     [
       {"Authorization", "Basic YWRtaW46YWRtaW4="},
       {"Accept", "*/*"},
       {"Content-Type", "application/x-www-form-urlencoded"},
       {"Content-Length", "125"}
     ], nil)

which the parametre I stated “nil” which will not give me result. After adjustment it works !

which is now

{:ok, conn, request_ref} = Mint.HTTP1.request(conn, "POST", "/default/en_US/sms_info.html?",
     [
       {"Authorization", "Basic YWRtaW46YWRtaW4="},
       {"Accept", "*/*"},
       {"Content-Type", "application/x-www-form-urlencoded"},
       {"Content-Length", "125"}
     ], "line=1&action=#{action}&telnum=#{telnum}&smscontent=#{smscontent}&smskey=1162480578")

the output is something like this now

{:ok,
 %Mint.HTTP1{
   buffer: "",
   host: "[my-ip-i-cant-show]",
   mode: :active,
   port: 80,
   private: %{},
   request: %{
     body: nil,
     connection: [],
     content_length: nil,
     data_buffer: [],
     headers_buffer: [],
     method: "POST",
     ref: #Reference<0.1063083407.3741843458.16189>,
     state: :status,
     status: nil,
     transfer_encoding: [],
     version: nil
   },
   requests: {[], []},
   scheme_as_string: "http",
   socket: #Port<0.6>,
   state: :closed,
   transport: Mint.Core.Transport.TCP
 }}