Although firewalls and other security features can block malicious traffic from accessing your website, they may accidentally block good traffic too. To import data or send shipment notifications to your site, XPS Ship must be able to communicate with the store. If your firewall is blocking the request from XPS Ship it may show an error on your integration preventing orders from populating into the system, or preventing XPS from updating your orders after booking.
To resolve you will need to contact your hosting ISP or network administrator to white list the following IP Addresses:
54.86.229.202
184.72.99.198
107.22.199.173