If you have checked the common issues that keep VMcast from playing properly, here are additional troubleshooting steps you may find helpful.
Clear VMcast app cache
Sometimes a downloaded file may be corrupted on your device. For example, you may see a “Video Load Error” or “Content Load Error” when you play your loop.
Clear all VMcast app preferences
Sometimes it may be necessary to remove all of your VMcast app data and downloaded content from the device.
Update the Amazon FireOS
Updates are often needed to ensure that the device and its apps run properly. Often, these updates are done automatically, but you may need to manually update your device if you are experiencing playback issues.
Reinstall the VMcast app
Sometimes it may be necessary to start with a clean slate and reinstall the VMcast app on your device.
Factory reset an Amazon Fire TV Stick
If you have gone through all of the above and are still experiencing playback issues, you may need to "Factory Reset" your current device.