diff --git a/ncc/certs.py b/ncc/certs.py
index 4d4594a..89ad62a 100644
--- a/ncc/certs.py
+++ b/ncc/certs.py
@@ -65,7 +65,7 @@ def get_sites(cfg: Path) -> Generator[Tuple[Path, str]]:
         config_part = _remove_comments(c[1])
 
         for server_block in _get_server_blocks(config_part):
-            sn = next(re.finditer(SERVER_NAME_RE, server_block))
+            sn = next(re.finditer(SERVER_NAME_RE, server_block), None)
             if not sn:
                 continue