Why does my rca viking tablet always says authentication problem; i tried everything. can you help me?

In my home network setup, when the wireless protocol was set as Mixed WPA2/WPA-PSK, initially all wireless devices (2 laptops, 3 tablets, 2 smartphones) could be connected. However, after disconnecting any wireless device, all attempts at reconnection failed, unless the router and the Optical Network Terminal (ONT) were rebooted. My Lenovo tablet, iPad, Xiaomi phone, iPhone and other portable Wi-Fi devices reported an authentication problem. This process of rebooting the router and ONT had to be repeated every time one of the devices was disconnected.

However, when the wireless protocol was changed to WEP-Shared (64-bit), there was no problem connecting and the router and ONT did not have to be rebooted even after disconnecting the wireless devices.

Of course, this is not a permanent solution since the security level is minimal, but at least it gets the wireless network connecting again.

Source: Why does my rca viking tablet always says authentication problem; i tried everything. can you help me?