From 9876cd6e77e102f860c313995b8b7c38e9297853 Mon Sep 17 00:00:00 2001
From: habcawa <212562656+habcawa@users.noreply.github.com>
Date: Tue, 20 May 2025 16:19:09 +0200
Subject: [PATCH] fix(MtProtoSender): improve error handling on
 BadMsgNotification for seq_no too low/too high

---
 telethon/network/mtprotosender.py | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/telethon/network/mtprotosender.py b/telethon/network/mtprotosender.py
index f1ebcac6..f813af63 100644
--- a/telethon/network/mtprotosender.py
+++ b/telethon/network/mtprotosender.py
@@ -824,12 +824,11 @@ class MTProtoSender:
                 correct_msg_id=message.msg_id)
             self._log.info('System clock is wrong, set time offset to %ds', to)
         elif bad_msg.error_code == 32:
-            # msg_seqno too low, so just pump it up by some "large" amount
-            # TODO A better fix would be to start with a new fresh session ID
-            self._state._sequence += 64
+            # msg_seqno too low
+            self._state.reset(keep_key=True)
         elif bad_msg.error_code == 33:
-            # msg_seqno too high never seems to happen but just in case
-            self._state._sequence -= 16
+            # msg_seqno too high
+            self._state.reset(keep_key=True)
         else:
             for state in states:
                 state.future.set_exception(