Maintenance countdown warning message - modal pop-up window? is it a good practice for such a important message

1. What is the difference between popup and modal?
2. What is the difference between popover and pop up?

What is the difference between popup and modal?

Modals, like pop-ups, are components that pop up on a user's screen. The key difference, however, is that the user would have initiated the action as part of their journey. Modals are used for specific workflows such as adding users, deleting content, sharing content, adding content, and more.

What is the difference between popover and pop up?

Because popups are often used to serve alerts and ads, most modern browsers include a popup block setting, and some have it activated by default. The average user can't see popup windows. A popover (also known as an overlay, a modal, or interstitial) is part of the actual web page.