It sounds like the connection between your worksheet and the external data source has been lost or disabled. Here are a few steps you can try to resolve the issue:

1. Check if the data source is still available: Make sure that the external data source is still accessible and that you have the necessary permissions to access it. If the data source has been moved or deleted, you may need to update the connection information.
   
2. Check if the connection is enabled: Go to the Data tab in the Excel ribbon and click on Connections. Select the connection that you are using and click on Properties. Make sure that the Enable background refresh and Enable refresh on open options are checked.
   
3. Check if the connection is set to refresh automatically: In the same Properties window, check if the Refresh data when opening the file and Refresh every X minutes options are checked. This will ensure that your data is always up-to-date.
   
4. Check if the connection is set to refresh on demand: If the connection is set to refresh on demand, you will need to manually refresh the data by clicking on the Refresh All button in the Data tab.
   
5. Check if the connection is password protected: If the connection is password protected, you may need to enter the password before you can edit the query or refresh the data.

If none of these steps work, you may need to recreate the connection to the external data source. To do this, go to the Data tab in the Excel ribbon and click on From Other Sources. Select the type of data source you are using and follow the prompts to create a new connection. Once the connection is established, you should be able to edit the query and refresh the data as needed.