After you added an Event countdown block in the email builder or the landing page builder, it showed a grey box that said “Count down to your event’s date and time” where the timer should be.
The block now shows the timer on the canvas, styled the way you set it up. When you click Change countdown and pick a new date, style or background, the canvas updates as soon as you save. Preview, sent emails and published landing pages show the same timer, current as of when the email is opened or the page is viewed.
When Show is set to Days, the time is now optional. Leave it blank and the countdown counts the days to the date, and the Banner style shows just the date.
If you added a countdown that only ever showed the grey box, delete it and add it again.