diff --git a/src/include/switch_core_media.h b/src/include/switch_core_media.h
index c021d0a90e..9df7a71251 100644
--- a/src/include/switch_core_media.h
+++ b/src/include/switch_core_media.h
@@ -253,6 +253,7 @@ SWITCH_DECLARE(void) switch_core_media_set_telephony_event(switch_core_session_t
 SWITCH_DECLARE(void) switch_core_media_set_telephony_recv_event(switch_core_session_t *session, switch_media_type_t type, switch_payload_t te);
 SWITCH_DECLARE(switch_rtp_stats_t *) switch_core_media_stats(switch_core_session_t *session, switch_media_type_t type, switch_memory_pool_t *pool);
 SWITCH_DECLARE(switch_status_t) switch_core_media_udptl_mode(switch_core_session_t *session, switch_media_type_t type);
+SWITCH_DECLARE(switch_bool_t) switch_core_media_check_udptl_mode(switch_core_session_t *session, switch_media_type_t type);
 
 SWITCH_DECLARE(void) switch_core_media_set_rtp_flag(switch_core_session_t *session, switch_media_type_t type, switch_rtp_flag_t flag);
 SWITCH_DECLARE(void) switch_core_media_clear_rtp_flag(switch_core_session_t *session, switch_media_type_t type, switch_rtp_flag_t flag);
diff --git a/src/mod/endpoints/mod_sofia/sofia.c b/src/mod/endpoints/mod_sofia/sofia.c
index 053c1c5b25..c6032cbd26 100644
--- a/src/mod/endpoints/mod_sofia/sofia.c
+++ b/src/mod/endpoints/mod_sofia/sofia.c
@@ -6758,7 +6758,7 @@ static void sofia_handle_sip_i_state(switch_core_session_t *session, int status,
 	}
 
 	if (session) {
-		if (switch_channel_test_flag(channel, CF_ANSWERED) && (status == 180 || status == 183) && !r_sdp) {
+		if ((switch_channel_test_flag(channel, CF_ANSWERED) && (status == 180 || status == 183) && !r_sdp) || (ss_state == nua_callstate_ready && status >= 300)) {
 			switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_DEBUG, "Channel %s skipping state [%s][%d]\n",
 							  switch_channel_get_name(channel), nua_callstate_name(ss_state), status);
 			goto done;
@@ -9157,7 +9157,14 @@ void sofia_handle_sip_i_reinvite(switch_core_session_t *session,
 				tech_pvt->mparams.last_sdp_str = tech_pvt->mparams.prev_sdp_str;
 			}
 		}
-		switch_channel_execute_on(channel, "execute_on_sip_reinvite");
+
+		if (switch_core_media_check_udptl_mode(session, SWITCH_MEDIA_TYPE_AUDIO)) {
+			/* Refuse all re-invites once we are doing T.38 */
+			nua_respond(nh, SIP_488_NOT_ACCEPTABLE, TAG_END());
+			switch_channel_hangup(channel, SWITCH_CAUSE_INCOMPATIBLE_DESTINATION);
+		} else {
+			switch_channel_execute_on(channel, "execute_on_sip_reinvite");
+		}
 	}
 
 }
diff --git a/src/switch_core_media.c b/src/switch_core_media.c
index 517f1e9f41..a18b493929 100644
--- a/src/switch_core_media.c
+++ b/src/switch_core_media.c
@@ -9579,6 +9579,24 @@ SWITCH_DECLARE(switch_rtp_stats_t *) switch_core_media_get_stats(switch_core_ses
 	return NULL;
 }
 
+//?
+SWITCH_DECLARE(switch_bool_t) switch_core_media_check_udptl_mode(switch_core_session_t *session, switch_media_type_t type)
+{
+	switch_media_handle_t *smh;
+
+	switch_assert(session);
+
+	if (!(smh = session->media_handle)) {
+		return SWITCH_STATUS_FALSE;
+	}
+
+	if (switch_rtp_ready(smh->engines[type].rtp_session)) {
+		return switch_rtp_test_flag(smh->engines[type].rtp_session, SWITCH_RTP_FLAG_UDPTL) ? SWITCH_TRUE : SWITCH_FALSE;
+	}
+
+	return SWITCH_FALSE;
+}
+
 //?
 SWITCH_DECLARE(switch_status_t) switch_core_media_udptl_mode(switch_core_session_t *session, switch_media_type_t type)
 {