Hi, welcome to this forum!
If the thermostat is working well, then the problem is only in the client app. May you tell me what android device you have (manufacturer and android version).
Probably it has to do with the energy savings policies that some manufacturers add to the devices.
Take a look in our faq section, to the question “Why is the client app not receiving data from the thermostat or vice versa?”:
Let me know if that solves the issue or not.
Thanks!