If you're seeing mostly UPS / FedEx (or NON-USPS) shipping come through, presuming you use real time shipping, today, there's a reason as the USPS rate server(s) API has been having issues since late last night (0400HRS, EST, 14-JUN-2020)
https://www.shippingapimonitor.com/h....html?api=usps
USPS_API.jpg
https://www.shippingapimonitor.com/h....html?api=usps
USPS_API.jpg