diff --git a/pyrogram/crypto/mtproto.py b/pyrogram/crypto/mtproto.py
index 81cf56f4..a22693fe 100644
--- a/pyrogram/crypto/mtproto.py
+++ b/pyrogram/crypto/mtproto.py
@@ -20,7 +20,7 @@ import bisect
 from hashlib import sha256
 from io import BytesIO
 from os import urandom
-from typing import Optional, List
+from typing import List, Tuple
 
 from pyrogram.raw.core import Message, Long
 from . import aes
@@ -58,7 +58,7 @@ def unpack(
     auth_key: bytes,
     auth_key_id: bytes,
     stored_msg_ids: List[int]
-) -> Optional[Message]:
+) -> Tuple[Message, bool]:
     assert b.read(8) == auth_key_id, b.getvalue()
 
     msg_key = b.read(16)
@@ -103,22 +103,22 @@ def unpack(
     if stored_msg_ids:
         # Ignored message: msg_id is lower than all of the stored values
         if message.msg_id < stored_msg_ids[0]:
-            return None
+            return message, False
 
         # Ignored message: msg_id is equal to any of the stored values
         if message.msg_id in stored_msg_ids:
-            return None
+            return message, False
 
         time_diff = (message.msg_id - MsgId()) / 2 ** 32
 
         # Ignored message: msg_id belongs over 30 seconds in the future
         if time_diff > 30:
-            return None
+            return message, False
 
         # Ignored message: msg_id belongs over 300 seconds in the past
         if time_diff < -300:
-            return None
+            return message, False
 
     bisect.insort(stored_msg_ids, message.msg_id)
 
-    return message
+    return message, True
diff --git a/pyrogram/session/session.py b/pyrogram/session/session.py
index 39fe605c..b3875f3c 100644
--- a/pyrogram/session/session.py
+++ b/pyrogram/session/session.py
@@ -220,17 +220,22 @@ class Session:
         await self.start()
 
     async def handle_packet(self, packet):
-        data = await self.loop.run_in_executor(
-            pyrogram.crypto_executor,
-            mtproto.unpack,
-            BytesIO(packet),
-            self.session_id,
-            self.auth_key,
-            self.auth_key_id,
-            self.stored_msg_ids
-        )
+        try:
+            data, ok = await self.loop.run_in_executor(
+                pyrogram.crypto_executor,
+                mtproto.unpack,
+                BytesIO(packet),
+                self.session_id,
+                self.auth_key,
+                self.auth_key_id,
+                self.stored_msg_ids
+            )
+        except AssertionError:
+            self.connection.close()
+            return
 
-        if data is None:
+        if not ok:
+            self.connection.close()
             return
 
         messages = (