Try these steps in order:
Check if Airplane Mode is enabled (Settings > Connections > Airplane Mode) — turn it off if active;
Toggle the Wi-Fi switch off and on again to refresh the network scan;
Move your tablet closer to the Wi-Fi router (avoid walls, metal obstacles, or long distances);
Confirm the router is powered on and Wi-Fi is enabled (check with another device);
Restart your tablet: Press Power button and Volume up button at the same time, then click Restart from the pop out window;
If the router’s SSID is hidden, manually add the network (see Q1, Step 5).
