diff --git a/swh/lister/phabricator/lister.py b/swh/lister/phabricator/lister.py
--- a/swh/lister/phabricator/lister.py
+++ b/swh/lister/phabricator/lister.py
@@ -97,14 +97,7 @@
             )
             response = self.session.post(self.url, data=params)
 
-            if response.status_code != 200:
-                logger.warning(
-                    "Got unexpected status_code %s on %s: %s",
-                    response.status_code,
-                    response.url,
-                    response.content,
-                )
-                break
+            response.raise_for_status()
 
             response_data = response.json()
 
diff --git a/swh/lister/phabricator/tests/test_lister.py b/swh/lister/phabricator/tests/test_lister.py
--- a/swh/lister/phabricator/tests/test_lister.py
+++ b/swh/lister/phabricator/tests/test_lister.py
@@ -7,6 +7,7 @@
 from pathlib import Path
 
 import pytest
+from requests.exceptions import HTTPError
 
 from swh.lister import USER_AGENT
 from swh.lister.phabricator.lister import PhabricatorLister, get_repo_url
@@ -111,3 +112,24 @@
     scheduler_origins = swh_scheduler.get_listed_origins(lister.lister_obj.id).origins
 
     assert len(scheduler_origins) == expected_nb_origins
+
+
+def test_lister_request_error(
+    swh_scheduler, requests_mock, phabricator_repositories_page1,
+):
+    FORGE_BASE_URL = "https://forge.softwareheritage.org"
+
+    lister = PhabricatorLister(
+        scheduler=swh_scheduler, url=FORGE_BASE_URL, instance="swh", api_token="foo"
+    )
+
+    requests_mock.post(
+        f"{FORGE_BASE_URL}{lister.API_REPOSITORY_PATH}",
+        [
+            {"status_code": 200, "json": phabricator_repositories_page1},
+            {"status_code": 500, "reason": "Internal Server Error"},
+        ],
+    )
+
+    with pytest.raises(HTTPError):
+        lister.run()