Preventing session timeout

By default, WordPress makes your login session cookie expire in 48 hours (or on browser close), or 14 days if you check the “Remember Me” box.

Maybe you have some plugins which force your login cookie to expire.

You could manually add the code below on your functions.php to extend your cookie expiry to whatever timeframe you like. You can, in essence, stop WordPress from ever logging you out by changing the number of seconds to be a much higher number.

add_filter( 'auth_cookie_expiration', 'keep_me_logged_in_for_1_year' );
function keep_me_logged_in_for_1_year( $expirein ) {
    return YEAR_IN_SECONDS; // 1 year in seconds
}

Or you can also use this plugin to change the time limit: Configure Login Timeout

Hope that helps!!