diff --git a/lib/fluent/plugin/in_forward.rb b/lib/fluent/plugin/in_forward.rb
index 070d6e480f..6c27c0ea6d 100644
--- a/lib/fluent/plugin/in_forward.rb
+++ b/lib/fluent/plugin/in_forward.rb
@@ -211,7 +211,7 @@ def handle_connection(conn)
           options = on_message(msg, chunk_size, conn)
           if options && r = response(options)
             log.trace "sent response to fluent socket", address: conn.remote_addr, response: r
-            conn.on_write_complete{ conn.close } if @deny_keepalive
+            conn.on(:write_complete) { |c| c.close } if @deny_keepalive
             send_data.call(serializer, r)
           else
             if @deny_keepalive
diff --git a/lib/fluent/plugin/out_forward.rb b/lib/fluent/plugin/out_forward.rb
index fb9d642d1e..00bc2cc125 100644
--- a/lib/fluent/plugin/out_forward.rb
+++ b/lib/fluent/plugin/out_forward.rb
@@ -420,7 +420,7 @@ def on_heartbeat(sockaddr, msg)
     # return chunk id to be committed
     def read_ack_from_sock(sock, unpacker)
       begin
-        raw_data = sock.recv(@read_length)
+        raw_data = sock.instance_of?(Fluent::PluginHelper::Socket::WrappedSocket::TLS) ? sock.readpartial(@read_length) : sock.recv(@read_length)
       rescue Errno::ECONNRESET
         raw_data = ""
       end
diff --git a/test/plugin/test_out_forward.rb b/test/plugin/test_out_forward.rb
index f31c3c4508..1e78db92f9 100644
--- a/test/plugin/test_out_forward.rb
+++ b/test/plugin/test_out_forward.rb
@@ -430,6 +430,49 @@ def read_ack_from_sock(sock, unpacker)
     assert_empty d.instance.exceptions
   end
 
+  data('ack true' => true,
+       'ack false' => false)
+  test 'TLS transport and ack parameter combination' do |ack|
+    input_conf = TARGET_CONFIG + %[
+                   <transport tls>
+                     insecure true
+                   </transport>
+                 ]
+    target_input_driver = create_target_input_driver(conf: input_conf)
+
+    output_conf = %[
+      send_timeout 5
+      require_ack_response #{ack}
+      transport tls
+      tls_insecure_mode true
+      <server>
+        host #{TARGET_HOST}
+        port #{TARGET_PORT}
+      </server>
+      <buffer>
+        #flush_mode immediate
+        flush_interval 0s
+        flush_at_shutdown false # suppress errors in d.instance_shutdown
+      </buffer>
+    ]
+    @d = d = create_driver(output_conf)
+
+    time = event_time("2011-01-02 13:14:15 UTC")
+    records = [{"a" => 1}, {"a" => 2}]
+    target_input_driver.run(expect_records: 2, timeout: 3) do
+      d.run(default_tag: 'test', wait_flush_completion: false, shutdown: false) do
+        records.each do |record|
+          d.feed(time, record)
+        end
+      end
+    end
+
+    events = target_input_driver.events
+    assert{ events != [] }
+    assert_equal(['test', time, records[0]], events[0])
+    assert_equal(['test', time, records[1]], events[1])
+  end
+
   test 'a destination node not supporting responses by just ignoring' do
     target_input_driver = create_target_input_driver(response_stub: ->(_option) { nil }, disconnect: false)