diff --git a/swh/lister/nixguix/lister.py b/swh/lister/nixguix/lister.py
--- a/swh/lister/nixguix/lister.py
+++ b/swh/lister/nixguix/lister.py
@@ -32,6 +32,7 @@
 from swh.core.tarball import MIMETYPE_TO_ARCHIVE_FORMAT
 from swh.lister import TARBALL_EXTENSIONS
 from swh.lister.pattern import CredentialsType, StatelessLister
+from swh.lister.utils import is_valid_origin_url
 from swh.scheduler.model import ListedOrigin
 
 logger = logging.getLogger(__name__)
@@ -348,7 +349,7 @@
             if self.github_session
             else artifact_url
         )
-        if not origin:
+        if not origin or not is_valid_origin_url(origin):
             return None
         return ArtifactType.VCS, VCS(
             origin=origin, type=artifact_type, ref=artifact_ref
@@ -402,7 +403,7 @@
                 urls = []
                 for url in origin_urls:
                     urlparsed = urlparse(url)
-                    if urlparsed.scheme == "":
+                    if urlparsed.scheme == "" and not re.match(r"^\w+@[^/]+:", url):
                         logger.warning("Missing scheme for <%s>: fallback to http", url)
                         fixed_url = f"http://{url}"
                     else:
diff --git a/swh/lister/nixguix/tests/data/sources-failure.json b/swh/lister/nixguix/tests/data/sources-failure.json
--- a/swh/lister/nixguix/tests/data/sources-failure.json
+++ b/swh/lister/nixguix/tests/data/sources-failure.json
@@ -53,6 +53,16 @@
       "urls": [ "unknown://example.org/wrong-scheme-so-skipped.txt" ],
       "integrity": "sha256-wAEswtkl3ulAw3zq4perrGS6Wlww5XXnQYsEAoYT9fI="
     },
+    {
+      "type": "url",
+      "urls": [ "ssh://git@example.org:wrong-scheme-so-skipped.txt" ],
+      "integrity": "sha256-wAEswtkl3ulAw3zq4perrGS6Wlww5XXnQYsEAoYT9fI="
+    },
+    {
+      "type": "url",
+      "urls": [ "git@example.org:git-pseudourl/so-skipped" ],
+      "integrity": "sha256-wAEswtkl3ulAw3zq4perrGS6Wlww5XXnQYsEAoYT9fI="
+    },
     {
       "type": "url",
       "urls": [ "https://code.9front.org/hg/plan9front" ],
diff --git a/swh/lister/nixguix/tests/test_lister.py b/swh/lister/nixguix/tests/test_lister.py
--- a/swh/lister/nixguix/tests/test_lister.py
+++ b/swh/lister/nixguix/tests/test_lister.py
@@ -353,13 +353,20 @@
     )
 
     listed_result = lister.run()
-    # only the origin upstream is listed, every other entries are unsupported or incomplete
-    assert listed_result == ListerStats(pages=1, origins=1)
 
+    expected_origins = ["https://github.com/NixOS/nixpkgs"]
     scheduler_origins = lister.scheduler.get_listed_origins(
         lister.lister_obj.id
     ).results
-    assert len(scheduler_origins) == 1
+    scheduler_origin_urls = [orig.url for orig in scheduler_origins]
+
+    assert scheduler_origin_urls == expected_origins
+
+    # only the origin upstream is listed, every other entries are unsupported or incomplete
+    assert listed_result == ListerStats(pages=1, origins=1), (
+        f"Expected origins: {' '.join(expected_origins)}, got: "
+        f"{' '.join(scheduler_origin_urls)}"
+    )
 
     assert scheduler_origins[0].visit_type == "git"