Sending in-app notifications are very different in Android and iOS. In Android phones, depending on the type of the phone, the notifications might not be sent unless the person performs certain changes. For example, while Samsung phones or Google phones work as expected, Huawei and Xiaomi phones sometimes don’t send any notifications to preserve battery, and the participant have to explicitly disable this feature which is not very straightforward. The conversation above, and this website explain more.
This issue does not exist in iPhones. As all iPhones are made by Apple, they all behave more or less the same, and this consistency has allowed us to be more certain about notifications being prompted on those devices.
But unfortunately, due to technical reasons, we cannot know when a notifications was sent. It’s not like sending an SMS or email where we can have a receipt confirmation. We only create a time-table of when we want the notifications to be prompted, and send that time-table to iPhone (and Android), and the rest is taken care of by the phone. We do not get any update or confirmation of any sort. So if you go to the
Adherence -> Survey Sessions and correct times are shown there, it means we have asked the phone to prompt the participant at these times. If a given participant does not receive the prompts, very likely either there is something incorrect about their phone settings, or they’ve missed the notification (note that unlike SMS or Email, in app notifications can be dismissed and they wont see it until they open the app or via the red notification indicator in the app’s logo).
Regardless, if you provide more specific details about this case, including who experienced this issue, and which notifications specifically where not sent, we will do whatever we can to find out the reason where possible.
The conversation on this post also can help to better understand my comments above.
Hope it helps.