I suspect it has something to do with the pre- and post idle timeouts.
The phones will show that they're connected to the WLAN, but they're not able to send or receive any data. Web pages just sit spinning their wheels. Or sometimes they'll show connected to LTE and the WiFi settings menu shows them trying to connect to the SSID with a "No Internet Connection" error message.
Anyone else having this issue? Recommended values for idle timeouts and session duration for a WPA2-PSK network?
Best answer by Ronald Dvorak