You may not be in range of the blinds. In this case you just need to move towards to the blinds until you are in range and the app show the option Tap to Connect.
The blind may not be powered. If it’s a battery-driven blind, try charging the battery. If it’s a wired blind, make sure it’s properly connected to a power outlet.
The blind may be in use by another person in the house. In this case, the blind will be available to you as soon as nobody else is connected it.
The Bluetooth in your device may be turned off, you just need to turn it on. If you need help to enable the Bluetooth in your device, please check this article.