What should I check if the feeds are not being generated on a daily basis?

The first factor and the most important is cron. It is essential for the automatic feed generation to have cron constantly running on your server.

Cron is a task scheduler and works on a Unix or Linux hosting environment. It lets applications automatically run specific server actions (running apps, scripts and stuff) using a predefined schedule or simply at specified time points. It can be used by Magento 2 installation and by many other web applications, such as our Product Feed.

As a first troubleshooting step, you can proceed to Stores → Configuration → Amasty Extensions → Extensions and Notifications → expand the System Information Tab and check the info on 5 last running cron jobs. If you see the following result 

or dates shown way back in the past it means either cron is not configured in your Magento instance or got stuck and needs to be restarted. Here you can learn more about Magento cron and how it should be configured.

Alternatively, you can ask your system administrator or hosting provider to set up cron and check the scheduled generation again once it is configured.

The second reason for the missed feed generation at a specified time is the manual feed generation.

I mean if the scheduled feed was generated in manual mode. You can check the feed execution mode right on the feed grid.

This way, if the scheduled feed was generated manually it may take the feed up to 48 hours to run next daily generation routine as in the module code there is a check on when the last feed generation took place.