How annoying that you do not receive notifications from your Ring / Nest doorbell or camera. Often the cause is the quality of your Wi-Fi network.
As a first step, we recommend that you perform a speed test. Read more about this in our article about the speed test.
Then it is good to check the strength of your Wi-Fi channel. You may have to switch to a quieter channel. You can read more about this in our article about Wi-Fi analysers.
If the speed and channel are correct, try uninstalling and reinstalling the app. Do the same with the device. Also follow the steps in this article.
If this does not work yet, please contact us. Don't forget to give your order number and to indicate what you have already done to solve the problem.