There are 2 possibilities:
If you use a wireless WiFi connection, make sure your router is not too far from your Alibox, and that there are no obstacles between your Alibox and the router (examples: behind the television, in a cavity of the television cabinet, etc.). In this case, bring your Alibox closer to the router as close as possible.
Also make sure that the internet speed that goes to your Alibox is at least 10
2- The app you are using has a problem : you must do a reset of your Alibox. Click here to see how .