Hello, and thanks for reviewing the MEATER Pro Duo. We are sorry to hear that you are unable to connect your Duo to the app. The first thing to do in these situations is to make sure that your device is compatible, even if it is successfully installed, by checking for your phone's OS version at support.meater.com/faqs/compatible-devices. On that page will also be additional requirements, which are worth verifying for as well. Another reason something like this may occur is if the probes are already paired with a second smart device. To get around this, temporarily disable the Bluetooth on the other device until you have your phone connected. While these are just a couple of steps that can be tried, there are more that can be provided by MEATER Customer Service. And even though some times of day may be busier than others, we have agents available 365 days of the year, until 10:00 PM MT, so you should be able to reach us quickly, when it is still convenient for your schedule.