diff --git a/wikihow2zim/scraper.py b/wikihow2zim/scraper.py
index 91835c8..93717e0 100644
--- a/wikihow2zim/scraper.py
+++ b/wikihow2zim/scraper.py
@@ -44,7 +44,6 @@ class DomIntegrityError(Exception):
 
 class wikihow2zim(GlobalMixin):
     def __init__(self, **kwargs):
-
         Global.conf = Conf(**kwargs)
         for option in Global.conf.required:
             if getattr(Global.conf, option) is None:
@@ -326,11 +325,18 @@ def build_expected_categories(self):
 
             while query_list:
                 item = query_list.pop()
+                logger.debug(
+                    "Querying categorymembers of "
+                    f"{self.metadata['category_prefix']}:{item}"
+                )
                 for query in self.api_site.query(
                     list="categorymembers",
                     cmtitle=f"{self.metadata['category_prefix']}:{item}",
                     cmtype="subcat",
                 ):
+                    logger.debug(
+                        f"categorymembers returned: {query.get('categorymembers')}"
+                    )
                     for cat_member in query.get("categorymembers"):
                         # only interested in (sub)categories
                         if cat_member.get("ns") != 14: