diff --git a/swh/lister/sourceforge/lister.py b/swh/lister/sourceforge/lister.py
--- a/swh/lister/sourceforge/lister.py
+++ b/swh/lister/sourceforge/lister.py
@@ -195,10 +195,9 @@
         if response.status_code != 200:
             # Log response content to ease debugging
             logger.warning(
-                "Unexpected HTTP status code %s on %s: %s",
+                "Unexpected HTTP status code %s for URL %s",
                 response.status_code,
                 response.url,
-                response.content,
             )
         # The lister must fail on blocking errors
         response.raise_for_status()
@@ -294,7 +293,8 @@
                 else:
                     logger.debug("Project '%s' does not have any VCS", project)
             else:
-                # Should always match, let's log it
+                # Should almost always match, let's log it
+                # The only ones that don't match are mostly specialized one-off URLs.
                 msg = "Project URL '%s' does not match expected pattern"
                 logger.warning(msg, project_url)
 
@@ -324,11 +324,15 @@
                 msg = "New project during an incremental run: %s/%s"
                 logger.debug(msg, namespace, project)
 
-        res = self.page_request(endpoint, {}).json()
+        try:
+            res = self.page_request(endpoint, {}).json()
+        except requests.HTTPError:
+            # We've already logged in `page_request`
+            return []
 
         tools = res.get("tools")
         if tools is None:
-            # This probably never happens
+            # This rarely happens, on very old URLs
             logger.warning("Project '%s' does not have any tools", endpoint)
             return []
 
diff --git a/swh/lister/sourceforge/tests/test_lister.py b/swh/lister/sourceforge/tests/test_lister.py
--- a/swh/lister/sourceforge/tests/test_lister.py
+++ b/swh/lister/sourceforge/tests/test_lister.py
@@ -338,3 +338,58 @@
 
     with pytest.raises(HTTPError):
         lister.run()
+
+
+@pytest.mark.parametrize("status_code", [500, 503, 504, 403, 404])
+def test_sourceforge_lister_project_error(
+    datadir, swh_scheduler, requests_mock, status_code,
+):
+    lister = SourceForgeLister(scheduler=swh_scheduler)
+
+    requests_mock.get(
+        MAIN_SITEMAP_URL,
+        text=get_main_sitemap(datadir),
+        additional_matcher=_check_request_headers,
+    )
+    requests_mock.get(
+        "https://sourceforge.net/allura_sitemap/sitemap-0.xml",
+        text=get_subsitemap_0(datadir),
+        additional_matcher=_check_request_headers,
+    )
+    requests_mock.get(
+        "https://sourceforge.net/allura_sitemap/sitemap-1.xml",
+        text=get_subsitemap_1(datadir),
+        additional_matcher=_check_request_headers,
+    )
+    # Request mocks precedence is LIFO
+    requests_mock.get(
+        re.compile("https://sourceforge.net/rest/.*"),
+        json=functools.partial(get_project_json, datadir),
+        additional_matcher=_check_request_headers,
+    )
+    # Make all `mramm` requests fail
+    # `mramm` is in subsitemap 0, which ensures we keep listing after an error.
+    requests_mock.get(
+        re.compile("https://sourceforge.net/rest/p/mramm"), status_code=status_code
+    )
+
+    stats = lister.run()
+    # - os3dmodels (2 repos),
+    # - mojunk (3 repos),
+    # - backapps/website (1 repo).
+    # adobe and backapps itself have no repos.
+    # Did *not* list mramm
+    assert stats.pages == 3
+    assert stats.origins == 6
+
+    scheduler_origins = swh_scheduler.get_listed_origins(lister.lister_obj.id).results
+    res = {o.url: (o.visit_type, str(o.last_update.date())) for o in scheduler_origins}
+    # Ensure no `mramm` origins are listed, but all others are.
+    assert res == {
+        "svn.code.sf.net/p/backapps/website/code": ("svn", "2021-02-11"),
+        "git.code.sf.net/p/os3dmodels/git": ("git", "2017-03-31"),
+        "svn.code.sf.net/p/os3dmodels/svn": ("svn", "2017-03-31"),
+        "git.code.sf.net/p/mojunk/git": ("git", "2017-12-31"),
+        "git.code.sf.net/p/mojunk/git2": ("git", "2017-12-31"),
+        "svn.code.sf.net/p/mojunk/svn": ("svn", "2017-12-31"),
+    }