Sometimes the prices on the system stop moving because the data feed application stops due to feed vendor reasons. When a such case happened at your server, the only and best way to handle it, is to make a restart for the feed applications as following:

1. At first close the excel sheet if exist, after saving it to avoid deletion of recently added symbols.
2. Secondly, Close the feed application it self, also with saving it to keep the recently added settings, if exist.
3. Run the feed application again, and wait till it connected.
4. Run the Excel sheet, then you will be asked to make an update, confirm the update, then you will see that all prices will move again.

In order to avoid such case, you have to have backup feed and set the auto switching between them. In this case, you system will detect if a feed had stopped working completely and will automatically switched to the backup feed after certain number of seconds you define. You can read about "Backup feed"