Sometimes the rates aren't displayed and the user sees the message We are unable to obtain a rate quote for UPS shipping.

Could this error be caused by not connecting to the UPS server? If I reload the page or click Continue the page rates are displayed. It's a intermittent problem that doesn't happen all the time.

It also records this error in the logs:

PHP Warning: Invalid argument supplied for foreach() in /includes/modules/pages/checkout_shipping/header_php.php on line 205 for this code section line 205 is in bold

// check that the currently selected shipping method is still valid (in case a zone restriction has disabled it, etc)
if (isset($_SESSION['shipping']) && $_SESSION['shipping'] != FALSE && $_SESSION['shipping'] != '') {
$checklist = array();
foreach ($quotes as $key=>$val) {
foreach($val['methods'] as $key2=>$method) {
$checklist[] = $val['id'] . '_' . $method['id'];
}
}
$checkval = (is_array($_SESSION['shipping']) ? $_SESSION['shipping']['id'] : $_SESSION['shipping']);
if (!in_array($checkval, $checklist)) {
$messageStack->add('checkout_shipping', ERROR_PLEASE_RESELECT_SHIPPING_METHOD, 'error');
}
}

Thank you for reading this post. Your help would be greatly appreciated. and your help.