Why in android does my app die over time?

Question

HTML

I wrote an application similar to a very simple manager. When a message arrives, it should notify, and the alarm clock will go off when necessary.
But here's the problem, on phones where the power saving mode is turned on and the application dies after a while and stops notifying about new messages and the alarm clock. It is impossible to explain to each user that the application needs to be added to the exception, etc. Moreover, even on Chinese devices (Xiaomi, MIZUI, etc.) other applications work fine and do not die. A vivid example is whatsap, google calendar, "memory", etc. etc. Despite the fact that they are third-party (not regular programs from Xiaomi), they manage not to die. Notify about new messages, events coming over the network.
I want to understand what they used in the program to achieve this? What is his secret of vitality?

Answer 1

But here's the problem, I have Mi5

If we are talking about Xiaomi Mi5, then Chinese firmware notifications are usually one of the main problems. Applications need to be added to exceptions so that they are not unloaded from RAM and it is not a fact that they will come.
If possible, check on pure Android or on some non-Chinese firmware at least.