The devices which have been updated to the newest platform aren’t compatible with the MeShare app any longer.
With the Zmodo app, first log out (go to Me in the bottom left, then to log out), and log back in, check if the issue is resolved.
If you have cameras loaded alongside the NVR, you might try removing them and leaving only the NVR, as that might be causing a duplication in the video stream, making it too large to display correctly.
On the 1st channel that shows up, tap in the bottom left of the image to switch the display mode to low resolution before switching to the other cameras. The Zmodo app now starts in HD, where before everything started in LD. This can cause issues on some phones, or if you have a slower internet speed at the location where the system is installed.
Make sure the mobile device is running at least Android 5, has at least 2GB or RAM, and has a display resolution of at least 720x1280 pixels.