diff --git a/shelfmark/download/http.py b/shelfmark/download/http.py
index e52f01d..9bb3552 100644
--- a/shelfmark/download/http.py
+++ b/shelfmark/download/http.py
@@ -434,6 +434,24 @@ def html_get_page(
         except Exception as e:
             status = _get_status_code(e)
 
+            # DDoS-Guard also answers stale clearance cookies with an endless `?check=1`
+            # redirect. TooManyRedirects carries no status, so the 403 rescue below never
+            # fires and every retry re-sends the dead cookies.
+            if (
+                isinstance(e, requests.exceptions.TooManyRedirects)
+                and allow_bypasser_fallback
+                and _is_cf_bypass_enabled()
+                and not use_bypasser_now
+            ):
+                if not _is_using_external_bypasser():
+                    hostname = urlparse(current_url).hostname or ""
+                    _get_internal_bypasser().clear_cf_cookies(hostname)
+                logger.info("Redirect loop detected; switching to bypasser: %s", current_url)
+                if status_callback:
+                    status_callback("resolving", "Bypassing protection...")
+                use_bypasser_now = True
+                continue
+
             # 403 = Cloudflare/DDoS-Guard protection
             if status == _HTTP_STATUS_FORBIDDEN:
                 # If bypasser fallback is disabled, try mirrors instead
diff --git a/tests/download/test_http_bypasser_fallbacks.py b/tests/download/test_http_bypasser_fallbacks.py
index f159f7d..1716e8e 100644
--- a/tests/download/test_http_bypasser_fallbacks.py
+++ b/tests/download/test_http_bypasser_fallbacks.py
@@ -179,6 +179,65 @@ def test_challenged_search_switches_to_bypasser(monkeypatch):
     assert bypassed == ["https://annas-archive.gl/search?q=dune"]
 
 
+def test_redirect_loop_purges_stale_cookies_and_switches_to_bypasser(monkeypatch):
+    """A stale clearance cookie turns the gate into a `?check=1` redirect loop.
+
+    Guards the regression where TooManyRedirects carried no status code, so the
+    403-only rescue never fired and every retry re-sent the dead cookie.
+    """
+    import shelfmark.download.http as http
+
+    stale = {"__ddg8_": "stale"}
+    cleared: list[str] = []
+
+    class _FakeInternalBypasser:
+        @staticmethod
+        def clear_cf_cookies(domain: str) -> None:
+            cleared.append(domain)
+            stale.clear()
+
+    monkeypatch.setattr(http, "_is_cf_bypass_enabled", lambda: True)
+    monkeypatch.setattr(http, "_is_using_external_bypasser", lambda: False)
+    monkeypatch.setattr(http, "_get_internal_bypasser", lambda: _FakeInternalBypasser)
+    monkeypatch.setattr(http, "_bypass_grace_seconds", lambda: 100.0)
+    monkeypatch.setattr(http, "_apply_cf_bypass", lambda _url, _headers: dict(stale))
+    monkeypatch.setattr(http, "get_proxies", lambda _url: {})
+    monkeypatch.setattr(http, "get_ssl_verify", lambda _url: True)
+    monkeypatch.setattr(http.network, "should_rotate_dns_for_url", lambda _url: True)
+    monkeypatch.setattr(http.network, "is_aa_auto_mode", lambda: True)
+    monkeypatch.setattr(http.time, "sleep", lambda _seconds: None)
+
+    sent_cookies: list[dict[str, str]] = []
+
+    def check_redirect(url: str, **kwargs):
+        sent_cookies.append(kwargs["cookies"])
+        response = _FakeResponse(302, url=url)
+        response.is_redirect = True
+        response.headers = {"Location": f"{url}&check=1"}
+        return response
+
+    bypassed: list[str] = []
+    monkeypatch.setattr(http.requests, "get", check_redirect)
+    monkeypatch.setattr(
+        http,
+        "get_bypassed_page",
+        lambda url, *_a, **_k: bypassed.append(url) or "<table>results</table>",
+    )
+
+    html = http.html_get_page(
+        "https://annas-archive.gl/search?q=dune",
+        retry=10,
+        allow_bypasser_fallback=True,
+        success_delay=0,
+    )
+
+    assert html == "<table>results</table>"
+    assert cleared == ["annas-archive.gl"]
+    assert len(bypassed) == 1
+    # Escaped on the first exception, not retried with the dead cookie.
+    assert sent_cookies[0] == {"__ddg8_": "stale"}
+
+
 def test_download_url_ignores_zlib_cookie_refresh_failure(monkeypatch):
     import shelfmark.download.http as http