Missing alerts from outdoor cam

Installed 2 outdoor cams, which appear to be working but sporadically. A couple questions:

Very basic question: does the wyze app need to be running on my phone to get notifications?

Next: I am not getting all notifications, and, when I get them the video is delayed. For example, I had a delivery today, got a notification, but the video only showed the worker walking away.

?? any help is appreciated.