I guess you have configured an external list. Maybe you can let us know what you have confiigured there. The message showes that you have a timeout when the Web Gateway is trying to get data from this external list. You need to check if the Web Gateway is able to get connected to the external list to fetch the data. Right now it looks like this is not working.
But we are not set any external data, also we don't know where to configure the external data
Please create new service request using error description and attach Screenshot and feedback file. One of our Support Engineers will have a look to help you with this warning.
GUI -> Troubleshooting -> Feedback
CLI: /opt/mwg/bin/feedback.sh -l 2 (Path is shown at the end)