diff --git a/mtproto-client.c b/mtproto-client.c
index e65a05c..ff98063 100644
--- a/mtproto-client.c
+++ b/mtproto-client.c
@@ -1856,6 +1856,9 @@ void mtproto_close(struct mtproto_connection *mtp) {
     
     // remove all ping timer that point to this connection
     stop_ping_timer (mtp->connection);
+
+    // 
+    mtp->connection->session->c = 0;
 }
 
 /**
diff --git a/net.c b/net.c
index d935d1f..bbc54a2 100644
--- a/net.c
+++ b/net.c
@@ -619,6 +619,11 @@ void connections_poll_result (struct pollfd *fds, int max) {
 }
 
 int send_all_acks (struct session *S) {
+  logprintf ("send_all_acks()\n");
+  if (!S->c) {
+    logprintf ("WARNING: cannot send acks, session has no active connection");
+    return -1;
+  }
   struct mtproto_connection *mt = S->c->mtconnection;
   
   clear_packet (mt);
diff --git a/queries.c b/queries.c
index 06ee03a..8b42777 100644
--- a/queries.c
+++ b/queries.c
@@ -3075,6 +3075,9 @@ void do_update_typing (struct telegram *instance, peer_id_t id) {
 
 int telegram_has_output (struct telegram *instance)
 {
+    if (!instance->connection) {
+        return 0;
+    }
     if (instance->session_state == STATE_READY) {
         return tree_count_query (instance->queries_tree) > 0;
     }
diff --git a/telegram.c b/telegram.c
index 99492f5..49bffd1 100755
--- a/telegram.c
+++ b/telegram.c
@@ -160,6 +160,10 @@ void telegram_change_state (struct telegram *instance, int state, void *data)
             assert (instance->config->proxy_request_cb);
             // tell the proxy to close all connections
             instance->config->proxy_close_cb (instance, instance->connection->connection->fd);
+
+            // remove all left over queries and timers
+            free_timers (instance);
+            free_queries (instance);
             
             // start a new connection to the demanded data center. The pointer to the
             // new dc should was already updated by the on_error function of the query