diff --git a/c_src/quicer_listener.c b/c_src/quicer_listener.c
index f053f1e6..3367eedd 100644
--- a/c_src/quicer_listener.c
+++ b/c_src/quicer_listener.c
@@ -265,7 +265,6 @@ listen2(ErlNifEnv *env, __unused_parm__ int argc, const ERL_NIF_TERM argv[])
 
   QUIC_ADDR Address = {};
   HQUIC Registration = NULL;
-  char *cacertfile = NULL;
 
   QuicerRegistrationCTX *target_r_ctx = NULL;
 
@@ -283,77 +282,35 @@ listen2(ErlNifEnv *env, __unused_parm__ int argc, const ERL_NIF_TERM argv[])
   // Start build CredConfig from with listen opts
   QUIC_CREDENTIAL_CONFIG CredConfig;
 
-  // change from here
-  CxPlatZeroMemory(&CredConfig, sizeof(CredConfig));
-
-  CredConfig.Flags = QUIC_CREDENTIAL_FLAG_NONE;
-
-  if (!parse_cert_options(env, options, &CredConfig))
-    {
-      return ERROR_TUPLE_2(ATOM_QUIC_TLS);
-    }
+#if defined(QUICER_USE_TRUSTED_STORE)
+  X509_STORE *trusted_store = NULL;
+  ret = eoptions_to_cred_config(env, options, &CredConfig, &trusted_store);
+#else
+  ret = eoptions_to_cred_config(env, options, &CredConfig, NULL);
+#endif // QUICER_USE_TRUSTED_STORE
 
-  BOOLEAN is_verify = FALSE;
-  if (!parse_verify_options(env, options, &CredConfig, TRUE, &is_verify))
+  if (!IS_SAME_TERM(ret, ATOM_OK))
     {
-      return ERROR_TUPLE_2(ATOM_VERIFY);
-    }
-
-  if (!parse_cacertfile_option(env, options, &cacertfile))
-    {
-      // TLS opt error not file content error
-      free(cacertfile);
-      cacertfile = NULL;
-      free_certificate(&CredConfig);
-      return ERROR_TUPLE_2(ATOM_CACERTFILE);
+      return ERROR_TUPLE_2(ret);
     }
 
   // Now build l_ctx
   QuicerListenerCTX *l_ctx = init_l_ctx();
 
   if (!l_ctx)
-    {
-      free(cacertfile);
-      cacertfile = NULL;
+    { //@TODO free cacertfile?
       free_certificate(&CredConfig);
-      return ERROR_TUPLE_2(ATOM_ERROR_NOT_ENOUGH_MEMORY);
-    }
-  CxPlatRefInitialize(&l_ctx->ref_count);
-
-  if (is_verify && cacertfile)
-    {
-
-      // We do our own certificate verification against the certificates
-      // in cacertfile
-      // @see QUIC_CONNECTION_EVENT_PEER_CERTIFICATE_RECEIVED
-      CredConfig.Flags |= QUIC_CREDENTIAL_FLAG_INDICATE_CERTIFICATE_RECEIVED;
-
 #if defined(QUICER_USE_TRUSTED_STORE)
-      CredConfig.Flags |= QUIC_CREDENTIAL_FLAG_NO_CERTIFICATE_VALIDATION;
-      if (!build_trustedstore(cacertfile, &l_ctx->trusted_store))
-        {
-          ret = ERROR_TUPLE_2(ATOM_CERT_ERROR);
-          goto exit;
-        }
-#else
-      CredConfig.Flags |= QUIC_CREDENTIAL_FLAG_SET_CA_CERTIFICATE_FILE;
-      CredConfig.CaCertificateFile = cacertfile;
-#if defined(__APPLE__)
-      // This seems only needed for macOS
-      CredConfig.Flags
-          |= QUIC_CREDENTIAL_FLAG_USE_TLS_BUILTIN_CERTIFICATE_VALIDATION;
-#endif // __APPLE__
+      X509_STORE_free(trusted_store);
 #endif // QUICER_USE_TRUSTED_STORE
+      return ERROR_TUPLE_2(ATOM_ERROR_NOT_ENOUGH_MEMORY);
     }
-  else
-    { // NO verify peer
-#if !defined(QUICER_USE_TRUSTED_STORE)
-      CredConfig.Flags |= QUIC_CREDENTIAL_FLAG_NO_CERTIFICATE_VALIDATION;
+#if defined(QUICER_USE_TRUSTED_STORE)
+  l_ctx->trusted_store = trusted_store;
 #endif // QUICER_USE_TRUSTED_STORE
-      // since we don't use cacertfile, free it
-      free(cacertfile);
-      cacertfile = NULL;
-    }
+  CxPlatRefInitialize(&l_ctx->ref_count);
+
+  // *********  ANY ERROR below this line should goto `exit`   **************
 
   // Set owner for l_ctx
   if (!enif_self(env, &(l_ctx->listenerPid)))
@@ -405,20 +362,15 @@ listen2(ErlNifEnv *env, __unused_parm__ int argc, const ERL_NIF_TERM argv[])
     }
 
   // Now load server config
-  ERL_NIF_TERM estatus
-      = ServerLoadConfiguration(env,
+  ret = ServerLoadConfiguration(env,
                                 &options,
                                 Registration,
                                 &l_ctx->config_resource->Configuration,
                                 &CredConfig);
-
-#if defined(QUICER_USE_TRUSTED_STORE)
-  free(cacertfile);
-#endif // QUICER_USE_TRUSTED_STORE
-
-  if (!IS_SAME_TERM(ATOM_OK, estatus))
+  if (!IS_SAME_TERM(ATOM_OK, ret))
     {
-      ret = ERROR_TUPLE_3(ATOM_CONFIG_ERROR, estatus);
+      // @TODO unsure 3 elem tuple is the best way to return error
+      ret = ERROR_TUPLE_3(ATOM_CONFIG_ERROR, ret);
       goto exit;
     }
 
@@ -440,19 +392,23 @@ listen2(ErlNifEnv *env, __unused_parm__ int argc, const ERL_NIF_TERM argv[])
                       &l_ctx->Listener)))
     {
       // Server Configuration should be destroyed
+      // @FIXME here leaks config?
+      // enif_release_resource(l_ctx->config_resource);
       l_ctx->config_resource->Configuration = NULL;
       ret = ERROR_TUPLE_3(ATOM_LISTENER_OPEN_ERROR, ATOM_STATUS(Status));
       goto exit;
     }
   l_ctx->is_closed = FALSE;
 
-  // Link to registration
+  // Link to registration only when ListenerOpen success
   if (target_r_ctx)
     {
       enif_mutex_lock(target_r_ctx->lock);
       CxPlatListInsertTail(&target_r_ctx->Listeners, &l_ctx->RegistrationLink);
       enif_mutex_unlock(target_r_ctx->lock);
     }
+
+  // Now try to start listener
   unsigned alpn_buffer_length = 0;
   QUIC_BUFFER alpn_buffers[MAX_ALPN];
 
@@ -482,13 +438,16 @@ listen2(ErlNifEnv *env, __unused_parm__ int argc, const ERL_NIF_TERM argv[])
       ret = ERROR_TUPLE_3(ATOM_LISTENER_START_ERROR, ATOM_STATUS(Status));
       goto exit;
     }
-  ERL_NIF_TERM listenHandle = enif_make_resource(env, l_ctx);
 
+  ERL_NIF_TERM listenHandle = enif_make_resource(env, l_ctx);
+  // @TODO move it to earlier?
   free_certificate(&CredConfig);
   return OK_TUPLE_2(listenHandle);
 
 exit: // errors..
-  free(cacertfile);
+#if defined(QUICER_USE_TRUSTED_STORE)
+  X509_STORE_free(trusted_store);
+#endif // QUICER_USE_TRUSTED_STORE
   free_certificate(&CredConfig);
   destroy_l_ctx(l_ctx);
   return ret;
diff --git a/c_src/quicer_tls.c b/c_src/quicer_tls.c
index 2dd41422..4d4ce52e 100644
--- a/c_src/quicer_tls.c
+++ b/c_src/quicer_tls.c
@@ -298,3 +298,100 @@ parse_sslkeylogfile_option(ErlNifEnv *env,
   c_ctx->TlsSecrets = TlsSecrets;
   c_ctx->ssl_keylogfile = keylogfile;
 }
+
+/*
+** Convert eterm options (a map) to QUIC_CREDENTIAL_CONFIG
+**
+** @NOTE We zero reset CredConfig
+** @NOTE Also build trusted store if needed
+*/
+ERL_NIF_TERM
+eoptions_to_cred_config(ErlNifEnv *env,
+                        ERL_NIF_TERM eoptions,
+                        QUIC_CREDENTIAL_CONFIG *CredConfig,
+                        X509_STORE **trusted_store)
+{
+  BOOLEAN is_verify = FALSE;
+  char *cacertfile = NULL;
+  ERL_NIF_TERM ret = ATOM_OK;
+
+  CXPLAT_FRE_ASSERT(CredConfig);
+
+#if !defined(QUICER_USE_TRUSTED_STORE)
+  CXPLAT_FRE_ASSERT(trusted_store == NULL);
+#else
+  CXPLAT_FRE_ASSERT(trusted_store);
+#endif // QUICER_USE_TRUSTED_STORE
+
+  CxPlatZeroMemory(CredConfig, sizeof(QUIC_CREDENTIAL_CONFIG));
+
+  CredConfig->Flags = QUIC_CREDENTIAL_FLAG_NONE;
+
+  // Handle the certificate, key, password options
+  if (!parse_cert_options(env, eoptions, CredConfig))
+    {
+      return ATOM_QUIC_TLS;
+    }
+
+  // Handle the `verify` options
+  if (!parse_verify_options(env, eoptions, CredConfig, TRUE, &is_verify))
+    {
+      ret = ATOM_VERIFY;
+      goto exit;
+      ;
+    }
+
+  // Hanlde the `cacertfile` options
+  if (!parse_cacertfile_option(env, eoptions, &cacertfile))
+    {
+      // TLS opt error not file content error
+      ret = ATOM_CACERTFILE;
+      goto exit;
+    }
+
+  // Set flags for certificate verification
+  if (is_verify && cacertfile)
+    { // === START of verify peer with cacertfile === //
+
+      CredConfig->Flags |= QUIC_CREDENTIAL_FLAG_INDICATE_CERTIFICATE_RECEIVED;
+
+#if defined(QUICER_USE_TRUSTED_STORE)
+      // We do our own verification with the cacert in trusted_store
+      // @see QUIC_CONNECTION_EVENT_PEER_CERTIFICATE_RECEIVED
+      CredConfig->Flags |= QUIC_CREDENTIAL_FLAG_NO_CERTIFICATE_VALIDATION;
+      if (!build_trustedstore(cacertfile, trusted_store))
+        {
+          ret = ATOM_CERT_ERROR;
+          goto exit;
+        }
+
+      // Newly added @FIXME
+      free(cacertfile);
+#else
+      CredConfig->Flags |= QUIC_CREDENTIAL_FLAG_SET_CA_CERTIFICATE_FILE;
+      CredConfig->CaCertificateFile = cacertfile;
+#if defined(__APPLE__)
+      // This seems only needed for macOS
+      CredConfig->Flags
+          |= QUIC_CREDENTIAL_FLAG_USE_TLS_BUILTIN_CERTIFICATE_VALIDATION;
+#endif // __APPLE__
+#endif // QUICER_USE_TRUSTED_STORE
+    }  // === END of verify peer with cacertfile === //
+  else
+    { // NO verify peer
+#if !defined(QUICER_USE_TRUSTED_STORE)
+      CredConfig->Flags |= QUIC_CREDENTIAL_FLAG_NO_CERTIFICATE_VALIDATION;
+#endif // QUICER_USE_TRUSTED_STORE
+      // since we don't use cacertfile, free it
+      free(cacertfile);
+      cacertfile = NULL;
+    }
+  return ATOM_OK;
+
+exit:
+#if defined(QUICER_USE_TRUSTED_STORE)
+  free(cacertfile);
+#endif // QUICER_USE_TRUSTED_STORE
+  free_certificate(CredConfig);
+  return ret;
+}
diff --git a/c_src/quicer_tls.h b/c_src/quicer_tls.h
index 3aa5e724..90636b30 100644
--- a/c_src/quicer_tls.h
+++ b/c_src/quicer_tls.h
@@ -42,4 +42,10 @@ void free_certificate(QUIC_CREDENTIAL_CONFIG *cc);
 void parse_sslkeylogfile_option(ErlNifEnv *env,
                                 ERL_NIF_TERM options,
                                 QuicerConnCTX *c_ctx);
+
+ERL_NIF_TERM
+eoptions_to_cred_config(ErlNifEnv *env,
+                        ERL_NIF_TERM eoptions,
+                        QUIC_CREDENTIAL_CONFIG *CredConfig,
+                        X509_STORE **trusted_store);
 #endif // QUICER_TLS_H_
diff --git a/src/quicer_listener.erl b/src/quicer_listener.erl
index 4490b28c..048c3d98 100644
--- a/src/quicer_listener.erl
+++ b/src/quicer_listener.erl
@@ -147,6 +147,8 @@ handle_cast(_Request, State) ->
     | {noreply, NewState :: term(), Timeout :: timeout()}
     | {noreply, NewState :: term(), hibernate}
     | {stop, Reason :: normal | term(), NewState :: term()}.
+handle_info({quic, listener_stopped, L}, #state{listener = L} = State) ->
+    {stop, normal, State};
 handle_info(_Info, State) ->
     {noreply, State}.
 
diff --git a/test/quicer_SUITE.erl b/test/quicer_SUITE.erl
index 6ac8af0b..be8ca603 100644
--- a/test/quicer_SUITE.erl
+++ b/test/quicer_SUITE.erl
@@ -2911,7 +2911,9 @@ tc_peercert_server(Config) ->
     PeerCert =
         receive
             {SPid, peercert, Cert} ->
-                Cert
+                Cert;
+            {quic, transport_shutdown, Conn, _} = M ->
+                ct:fail("conn fail : ~p", [M])
         end,
     OTPCert = public_key:pkix_decode_cert(PeerCert, otp),
     ct:pal("client cert is ~p", [OTPCert]),
diff --git a/test/quicer_listener_SUITE.erl b/test/quicer_listener_SUITE.erl
index ada3d3a5..120d1b39 100644
--- a/test/quicer_listener_SUITE.erl
+++ b/test/quicer_listener_SUITE.erl
@@ -370,6 +370,18 @@ tc_stop_start_listener(Config) ->
     ok = snabbkaffe:retry(100, 10, fun() -> ok = quicer:start_listener(L, Port, LConf) end),
     ok = quicer:close_listener(L).
 
+tc_stop_start_listener_with_new_port(Config) ->
+    Port = select_port(),
+    LConf = default_listen_opts(Config),
+    {ok, L} = quicer:listen(Port, LConf),
+    ok = quicer:stop_listener(L),
+    Port2 = select_port(),
+    ok = snabbkaffe:retry(100, 10, fun() -> ok = quicer:start_listener(L, Port2, LConf) end),
+    {ok, Sock1} = gen_udp:open(Port),
+    ?assertMatch({error, eaddrinuse}, gen_udp:open(Port2)),
+    gen_udp:close(Sock1),
+    ok = quicer:close_listener(L).
+
 tc_stop_close_listener(Config) ->
     Port = select_port(),
     {ok, L} = quicer:listen(Port, default_listen_opts(Config)),