app android and iphone delay ringing the first call

[snowbike]

problem on multiple installations all onprem linux , pbx 3cx version 18.0.7.312; android app version 18.1.4.208; iphone app version 18.6.3.605. The rather strange thing is that I don't understand what to attribute the problem to since I tried to follow all the guides, especially those on push issues related to app energy saving. however I explain the problem (which happens both in wifi and in 4g, both on iphone and android without distinction): if the smartphone hasn't used the app for a while (about 3/4 min) or hasn't received calls, the first call it receives (for example from a landline) it rings after the 3/4 rings have already passed, now you'll say "it's a problem with the pbx that doesn't send the push" and here's the strange thing, because if I try again immediately after the same operation, the smartphone rings on the first ring of the calling party and it's not wrong only once until I go back to leaving the smartphone itself still for another 3/4 minutes (I repeat, it does it with any smartphone tested, be it apple or android, even if I disable all forms of energy saving) ... if I do the operation opposite, i.e. I try to call a landline extension from the smartphone with the app, no problem, the landline rings immediately... otherwise the PBX is a Swiss watch; I have to solve the problem as soon as possible, there is a risk of losing the call several times because the caller does not receive an answer in a timely manner.. ...thank you for any help

 

[ThomB_3CX]

@snowbike

Thanks for your feedback.

Could you also provide me in Private Message the app's verbose logs in order to understand what's going on and help you out with your issue? We will first check in logs for any issues related to push within the clients.

1. Enable Verbose Logs: “Android App Settings (top left hamburger menu) > Settings > Advanced > Troubleshooting > Enable verbose logging”.
2. Reproduce the issue and “Send log report”: Android App Settings (top left hamburger menu) > Settings > Advanced > Troubleshooting > Send Log Report

Thanks

 

[snowbike]

hi ThomB, thanks too
just time to get tested

 

[snowbike]

UPDATE info:
yesterday I did a test, because I'm stubborn and I wanted to understand what was the problem.. so I changed the hdd to the pc, I installed windows and its 3CX on the same machine, recovered the backup from the previous linux installation, the network structure was exactly the same as before .. result: problem solved immediately, no delay, everything synchronized on the first ring (wifi and 4g, iphone or android app, indiscriminately)... now, considering that 3cx recommends not to change anything on linux onprem installations and to use the distro debian packaged and optimized by 3cx itself (which I've always done), what could be the parameter on the linux installation, PBX or OS side, that escapes me to solve the problem? some idea?