diff --git a/swh/scanner/tests/flask_api.py b/swh/scanner/tests/flask_api.py
index 5d05dfd..f7664bb 100644
--- a/swh/scanner/tests/flask_api.py
+++ b/swh/scanner/tests/flask_api.py
@@ -13,6 +13,7 @@
 
 def create_app(tmp_requests, tmp_accesses):
     app = Flask(__name__)
+    app.config["SERVER_NAME"] = "localhost"
 
     @app.route("/")
     def index():