I am assuming that this error is related to the fedex rate quote servers taking up to 60 seconds to respond today, followed by an additional 5-10 seconds for the USPS rate quote servers to respond... while, the customer only sees a blank white screen waiting for a response or indication that something is happening.



Code:
[30-May-2020 13:05:45 America/Los_Angeles] Request URI: /index.php?main_page=checkout_shipping, IP address: 108.175.192.91
#1  trigger_error() called at [/home/chainwea/public_html/includes/classes/order.php:363]
#2  order->cart() called at [/home/chainwea/public_html/includes/classes/order.php:48]
#3  order->__construct() called at [/home/chainwea/public_html/includes/modules/pages/checkout_shipping/header_php.php:74]
#4  require(/home/chainwea/public_html/includes/modules/pages/checkout_shipping/header_php.php) called at [/home/chainwea/public_html/index.php:36]
--> PHP Notice: Malformed value for session-based shipping module; customer will need to re-select: false in /home/chainwea/public_html/includes/classes/order.php on line 363.