Countdown widget missing option "Action: block submit"

The Global Coundown widget no longer provides the option that once it runs out to block/hide the submit button and notify the user that they cannot submit.

From my tests you are using Countdown widget instead of Global Countdown:

Countdown widget does not have that option. 

You can inspect the demo form that uses the Global Countdown widget:

https://form.myjotform.com/61217082214546 

Let us know if we can assist you further.