diff --git a/sources/main.py b/sources/main.py
index a8f78f3..30b5b9d 100644
--- a/sources/main.py
+++ b/sources/main.py
@@ -136,6 +136,9 @@ async def generate_commit_list(tz):
 
     for repository in repos:
         result = await DownloadManager.get_remote_graphql("repository_committed_dates", owner=repository["owner"]["login"], name=repository["name"], id=user.node_id)
+        if result["data"]["repository"] is None or result["data"]["repository"]["defaultBranchRef"] is None:
+            continue
+
         committed_dates = result["data"]["repository"]["defaultBranchRef"]["target"]["history"]["edges"]
         for committedDate in committed_dates:
             date = datetime.datetime.strptime(committedDate["node"]["committedDate"], "%Y-%m-%dT%H:%M:%SZ").replace(tzinfo=pytz.utc).astimezone(timezone(tz))