Changing Thermostat Batteries

Hello, after I changed the batteries to my radio thermostats, the thermostat seems not to work anymore. If I pushed the button I get no lights or messages o temperature reading. The app keep saying that the thermostat is connected and the batteries are low. If I try to get the greeting message to visualize in the thermostat through the app nothing happens. I check the battery orientation and that correct. Should I have something after changing the batteries?