diff --git a/td/mtproto/PingConnection.cpp b/td/mtproto/PingConnection.cpp
index 7b74ee6ba..64a261501 100644
--- a/td/mtproto/PingConnection.cpp
+++ b/td/mtproto/PingConnection.cpp
@@ -134,7 +134,7 @@ class PingConnectionPingPong final
   void on_container_sent(MessageId container_message_id, vector<MessageId> message_ids) final {
   }
 
-  Status on_pong(double ping_time, double pong_time) final {
+  Status on_pong(double ping_time, double pong_time, double current_time) final {
     pong_cnt_++;
     if (pong_cnt_ == 1) {
       rtt_ = Time::now();
diff --git a/td/mtproto/SessionConnection.cpp b/td/mtproto/SessionConnection.cpp
index 70cb4fbe5..391785a6c 100644
--- a/td/mtproto/SessionConnection.cpp
+++ b/td/mtproto/SessionConnection.cpp
@@ -428,7 +428,8 @@ Status SessionConnection::on_packet(const MsgInfo &info, const mtproto_api::pong
   auto get_time = [](int64 msg_id) {
     return static_cast<double>(msg_id) / (static_cast<uint64>(1) << 32);
   };
-  return callback_->on_pong(get_time(pong.ping_id_), get_time(pong.msg_id_));
+  return callback_->on_pong(get_time(pong.ping_id_), get_time(pong.msg_id_),
+                            auth_data_->get_server_time(Time::now_cached()));
 }
 
 Status SessionConnection::on_packet(const MsgInfo &info, const mtproto_api::future_salts &salts) {
diff --git a/td/mtproto/SessionConnection.h b/td/mtproto/SessionConnection.h
index ea633d60f..6515c543f 100644
--- a/td/mtproto/SessionConnection.h
+++ b/td/mtproto/SessionConnection.h
@@ -98,7 +98,7 @@ class SessionConnection final
     virtual void on_session_failed(Status status) = 0;
 
     virtual void on_container_sent(MessageId container_message_id, vector<MessageId> message_ids) = 0;
-    virtual Status on_pong(double ping_time, double pong_time) = 0;
+    virtual Status on_pong(double ping_time, double pong_time, double current_time) = 0;
 
     virtual Status on_update(BufferSlice packet) = 0;
 
diff --git a/td/telegram/net/Session.cpp b/td/telegram/net/Session.cpp
index 3ebf8f5ec..4077b6c5b 100644
--- a/td/telegram/net/Session.cpp
+++ b/td/telegram/net/Session.cpp
@@ -565,7 +565,7 @@ void Session::on_connected() {
   }
 }
 
-Status Session::on_pong(double ping_time, double pong_time) {
+Status Session::on_pong(double ping_time, double pong_time, double current_time) {
   constexpr int MAX_QUERY_TIMEOUT = 60;
   constexpr int MIN_CONNECTION_ACTIVE = 60;
   if (current_info_ == &main_connection_ &&
@@ -575,7 +575,8 @@ Status Session::on_pong(double ping_time, double pong_time) {
       status = Status::Error(PSLICE() << "No state info for " << unknown_queries_.size() << " queries from auth key "
                                       << auth_data_.get_auth_key().id() << " for "
                                       << format::as_time(Time::now() - current_info_->created_at_)
-                                      << " after ping sent at " << ping_time << " and answered at " << pong_time);
+                                      << " after ping sent at " << ping_time << " and answered at " << pong_time
+                                      << " with the current server time " << current_time);
     }
     if (!sent_queries_list_.empty()) {
       for (auto it = sent_queries_list_.prev; it != &sent_queries_list_; it = it->prev) {
@@ -585,7 +586,8 @@ Status Session::on_pong(double ping_time, double pong_time) {
             status =
                 Status::Error(PSLICE() << "No answer from auth key " << auth_data_.get_auth_key().id() << " for "
                                        << query->net_query_ << " for " << format::as_time(Time::now() - query->sent_at_)
-                                       << " after ping sent at " << ping_time << " and answered at " << pong_time);
+                                       << " after ping sent at " << ping_time << " and answered at " << pong_time
+                                       << " with the current server time " << current_time);
           }
           query->is_acknowledged_ = false;
         } else {
diff --git a/td/telegram/net/Session.h b/td/telegram/net/Session.h
index 803eb1116..8572757bb 100644
--- a/td/telegram/net/Session.h
+++ b/td/telegram/net/Session.h
@@ -208,7 +208,7 @@ class Session final
   void on_connected() final;
   void on_closed(Status status) final;
 
-  Status on_pong(double ping_time, double pong_time) final;
+  Status on_pong(double ping_time, double pong_time, double current_time) final;
 
   void on_network(bool network_flag, uint32 network_generation);
   void on_online(bool online_flag);