"Waiting for Data" means that there is no data available in the IoT Central app for the time period specified in the dashboard tile.  It may or may not be expected depending on the device and circumstance.  Here are some examples related to the Presto Kit:

• For the Flic button, if no button presses have occurred in the time window it will indicate "waiting for data."  This is expected behavior.
• If a sensor device is out of range of the gateway and cannot send its data to IoT Central, it will indicate "waiting for data." Try moving the sensor closer to the gateway.
• If a sensor device battery expires or is disconnected, it will indicate "waiting for data."
• If the Cascade-500W is powered off, rebooting, or has lost network connection it will indicate "waiting for data."