diff --git a/plugins/slicer/MONAILabel/MONAILabel.py b/plugins/slicer/MONAILabel/MONAILabel.py
index df0ee1620..30db0dbcd 100644
--- a/plugins/slicer/MONAILabel/MONAILabel.py
+++ b/plugins/slicer/MONAILabel/MONAILabel.py
@@ -1365,7 +1365,7 @@ def getPermissionForImageDataUpload(self):
                 " will be sent to remote data processing server: {server_url}.\n\n"
                 "Click 'OK' to proceed with the segmentation.\n"
                 "Click 'Cancel' to not upload any data and cancel segmentation.\n"
-            ).format(self.serverUrl()),
+            ).format(server_url=self.serverUrl()),
             dontShowAgainSettingsKey="MONAILabel/showImageDataSendWarning",
         )