I've had issues in the past and I've noticed a couple of things.
1. make sure on a iOS device that under Privacy and security > Local network that the Meraki app is allowed.
2. When viewing footage viewing live works and anything older than 2 minutes works but if you try to view footage less than 2 mins old I get a no footage error as though either the camera or dashboard hasn't processed the footage yet.
3. If I am viewing a camera and leave the app and come back to it, I need to back out of the that camera and go back in for it to pickup the stream again.
I agree the app and experience isn't completely perfect but it is much better than it was.