I am encountering an HTTP error 400 when trying to reach reg.usps.com
USPS has verified their site is up.
The error is repeatable on all devices in household, connected to xfinity. On PCs, have tried multiple browsers, Chrome, Edge, with & without a private/incognito tab
The main site - www.usps.com - works fine.
All other websites work as expected.
https://www.usps.com works on PCs and phone's Xfinity WiFi connection.
https://informeddelivery.usps.com (similar login procedure as reg.usps.com) doesn't work on PC or phone's Xfinity WiFi connection.
https://reg.usps.com (you are redirected to this site from click & ship - cns.usps.com) doesn't work on PC or phone's Xfinity WiFi connection.
Informed Delivery site works OK on phone's LTE data connection.
reg.usps.com site works OK on phone's LTE data connection.
cns.usps.com site redirects to reg.usps.com and works OK on phone's LTE data connection.
Same results whether PC HOSTS is enabled or disabled.
Changing Windows 10 DNS from auto to Google DNS made no difference.
Flushing the Win 10 DNS cache made no difference.
Winsock reset made no difference.
"Protected Browsing" is OFF.
"Managed Sites" is Disabled.
Incognito browsing window made no difference.
Changed from Google DNS to OpenDNS in router settings Rebooted router multiple times Xfinity tier 1 support asked if www.americanexpress.com was working. Then they "provisioned" my modem and had me unplug/replug modem.
Xfinity support ticket is escalated but tier 2 agent said she would have to call her team and then call me back...
Browser results:
PC Google Chrome: "This page isn’t working... HTTP ERROR 400".
PC Edge: "This page isn’t working... HTTP ERROR 400"
Android chrome browser with Xfinity WiFi: "This page isn’t working... HTTP ERROR 400"
EDIT
Developer tools shows these errors:
(index):1 GET https://www.googletagmanager.com/gtm.js?id=%3CGTM-MVCC8H%3E net::ERR_ABORTED 404
(anonymous) @ (index):1 (anonymous) @ (index):1 cns.usps.com/:1199 Access to font at 'https://www.usps.com/assets/fonts/d5af76d8-a90b-4527-b3a3-182207cc3250.woff' from origin 'https://cns.usps.com' has been blocked by CORS policy: The 'Access-Control-Allow-Origin' header has a value 'https://www.usps.com' that is not equal to the supplied origin.
main-sb.css:1 GET https://www.usps.com/assets/fonts/d5af76d8-a90b-4527-b3a3-182207cc3250.woff net::ERR_FAILED 200
cns.usps.com/:1199 Access to font at 'https://www.usps.com/assets/fonts/4a9c62ab-b359-4081-8383-a0d1cdebd111.woff' from origin 'https://cns.usps.com' has been blocked by CORS policy: The 'Access-Control-Allow-Origin' header has a value 'https://www.usps.com' that is not equal to the supplied origin.
main-sb.css:1 GET https://www.usps.com/assets/fonts/4a9c62ab-b359-4081-8383-a0d1cdebd111.woff net::ERR_FAILED 200
cns.usps.com/:1199 Access to font at 'https://www.usps.com/assets/fonts/5b4a262e-3342-44e2-8ad7-719998a68134.woff' from origin 'https://cns.usps.com' has been blocked by CORS policy: The 'Access-Control-Allow-Origin' header has a value 'https://www.usps.com' that is not equal to the supplied origin.
main-sb.css:1 GET https://www.usps.com/assets/fonts/5b4a262e-3342-44e2-8ad7-719998a68134.woff net::ERR_FAILED 200
main.70fb2fe4.chunk.js:1 TypeError: Cannot read properties of undefined (reading 'items') at main.70fb2fe4.chunk.js:1:938322