diff --git a/voice.py b/voice.py
index aea4064..60c245b 100644
--- a/voice.py
+++ b/voice.py
@@ -709,6 +709,27 @@ class VoiceSession:
                     track_source = getattr(pub, 'source', None) or "unknown"
                     self._video_track = t
                     logger.info("Video track stored from %s source=%s for on-demand vision", p.identity, track_source)
+                    # Screen share starts → Element Call rotates E2EE key.
+                    # Proactively poll timeline for the new key instead of waiting
+                    # for DEC_FAILED (MAT-164).
+                    async def _proactive_key_poll(pid=p.identity):
+                        pre_key = self._caller_key
+                        for attempt in range(6):  # 6 × 500ms = 3s
+                            await asyncio.sleep(0.5)
+                            if self._caller_key != pre_key:
+                                logger.info("Proactive poll: key rotated via sync (attempt %d)", attempt + 1)
+                                return
+                            new_key = await self._fetch_encryption_key_http()
+                            if new_key and new_key != pre_key:
+                                logger.info("Proactive poll: got new key from timeline (attempt %d, %s)",
+                                            attempt + 1, new_key.hex()[:8])
+                                self.on_encryption_key(
+                                    self._caller_identity.split(":")[0] if self._caller_identity else "",
+                                    self._caller_identity.split(":")[-1] if self._caller_identity else "",
+                                    new_key, 0)
+                                return
+                        logger.info("Proactive poll: no key rotation after 3s")
+                    asyncio.ensure_future(_proactive_key_poll())
                 if int(t.kind) in (1, 2) and e2ee_opts is not None:  # audio + video tracks
                     caller_id = p.identity
                     track_type = "video" if int(t.kind) == 2 else "audio"
@@ -754,8 +775,8 @@ class VoiceSession:
                     now = time.monotonic()
                     if int(state) == 3:
                         _dec_failed_count[p_id] = _dec_failed_count.get(p_id, 0) + 1
-                        # After 3+ DEC_FAILED: re-fetch key from timeline (key may have rotated)
-                        if _dec_failed_count[p_id] >= 3 and not _refetch_in_progress:
+                        # After 1+ DEC_FAILED: re-fetch key from timeline (key may have rotated)
+                        if _dec_failed_count[p_id] >= 1 and not _refetch_in_progress:
                             _refetch_in_progress = True
                             _p_id_copy = p_id  # capture for closure
                             async def _refetch_key():
@@ -781,9 +802,9 @@ class VoiceSession:
                                 finally:
                                     _refetch_in_progress = False
                             asyncio.ensure_future(_refetch_key())
-                        # Cooldown: only re-key every 5s to avoid tight loops
+                        # Cooldown: only re-key every 2s to avoid tight loops
                         last = _last_rekey_time.get(p_id, 0)
-                        if (now - last) < 5.0:
+                        if (now - last) < 2.0:
                             return
                     _last_rekey_time[p_id] = now
                     if self._caller_all_keys: