A device sends its data to the Hub and the Hub sends the data to the cloud. When you don't see any sensor data in the dashboard there can be something wrong with the connection from the device to the Hub or with the connection from the Hub to the cloud.
First, you need to be sure that the Hub is working correctly. Therefore, read this article first. If you are sure the Hub is working, continue with the following steps:
Test if the device is working
Test the connection with the Hub