diff --git a/webservice/serve_overview.py b/webservice/serve_overview.py
index 2707b4f551d7ec0851c8a16cdc564c40355b00e9..dabfae7e46e6a84faca59061c4d3e940181c854b 100644
--- a/webservice/serve_overview.py
+++ b/webservice/serve_overview.py
@@ -276,7 +276,7 @@ class RequestHandler(BaseHTTPRequestHandler):
             tsize = 0
             for run in runs:
                 run = int(run)
-                if detector not in cal_config['data-mapping']:
+                if 'karabo-da' not in cal_config['data-mapping'].get(detector, {}):
                     continue
                 # ToDo calculate tsize based on selected karabo-da
                 for mp in cal_config['data-mapping'][detector]['karabo-da']: