Check your router and internet connection. Make sure both devices are online. Make sure both devices use the latest app version. Make sure to close all your background programs to release free resources of your device. The app can just stuck so try to close/kill the app by swiping out and starting it again. If the issue is network stability related just reboot your router and check for the internet connection. If it's not stable, switch both units to 3G, 4G, 5G, or LTE.