VMcast automatically downloads ViewMedica content to your loop to save bandwidth. However, a strong internet connection is still required by the app. If your device loses connectivity, you will see an offline message until the connection is reestablished.
Check for a strong internet connection
Press and hold the home button (⌂) on the Fire TV Stick remote for a few seconds. A quick access menu should appear covering the entire screen.
Select "Settings."
Select "Network."
Highlight your connected network and press the play/pause ( >|| ) button.
The details about your device’s connectivity will appear. Look for all green checkmarks. If there are issues found, please follow any of the recommendations listed there.