url rewrite parsing a custom url parameter not working

You’ll need to append the new variable (param1) to the public query variables:

add_filter("query_vars", function( $vars ){
    $vars[] = 'param1';
    return $vars;
});

Now you’ll be able to get the value of this param with get_query_var( 'param1' ).

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)