I had post my app after a long develpment period, I don't know why. but in some devices works well, but in others is difficult to notice what is going on. First: my app is a softphone voip, but keep app open or in background for our register be active is not effective because of battery safety. Then is when apns coming in, we just need that or app come back to be active, even in background, to our call shows up. and this happens well in our development enviroment, exacly like I describe. but in some devices doesn't work at all. We are using apns and firebase tokens to identify our registers and devices, and keeping together in our server/DB. I will share a image to explain better the flux that I implemented: Yes, I followed all instructions to insert apns, p12 and p8 certifies in the project, I just don't know why is working only in some devices. If anybody try test this function in my app, doesn't will work because I put some rules about IP address.