Locked out of USPS Informed Delivery in 2026: fixing MFA code failures, endless prompts, and “Authentication Failed”

USPS Informed Delivery is one of those services you don’t realize you depend on until it stops working—especially if you use the Daily Digest emails to watch for checks, replacement cards, legal mail, or time-sensitive packages.

In recent months (late 2025 into January 2026), a common pattern has emerged: people try to sign in and get stuck in an MFA loop (the code never arrives, arrives late, or expires), or they hit an error like “Authentication Failed… An unexpected internal system exception has occurred. Please try again later.” Users report trying multiple browsers/devices and still getting blocked. [4]

Below is a practical, low-cost checklist to get back in.

Who this affects

• Anyone using USPS Informed Delivery via USPS.com (web or app).
• People who created a USPS.com account on/after March 6, 2025 (MFA required). [1]
• People who frequently clear cookies, use private browsing, switch browsers/devices, or use aggressive ad/content blockers.
• People who depend on email verification links (which can be delayed or filtered).

Why it’s happening (what changed)

USPS states that beginning March 6, 2025, all new USPS.com accounts are required to enroll in multifactor authentication (MFA). Older accounts may have the option to enroll and can sometimes postpone prompts. [1]

MFA is good security, but it also means:

• If you can’t receive the one-time passcode (OTP) by email/SMS reliably, you can’t sign in.
• If your browser cookies get cleared (or you change devices), USPS may prompt you again.
• Some users also hit platform-side errors (“internal system exception”), which you can’t fully fix locally—but you can often work around them (or at least confirm it’s not your setup). [4]

Fixes (step-by-step)

Solution 1: Reduce “repeat MFA prompts” (device + cookies)

1. Sign in normally.
2. When prompted for the MFA code, look for “Remember my device” and enable it on a trusted personal device.
3. Avoid clearing cookies for USPS.com afterward.

USPS notes that “Remember my device” can prevent additional MFA prompts on that device for 30 days, but you’ll be prompted again if you clear cookies or switch browsers/devices. [1]

Solution 2: If the code never arrives, fix deliverability first (fastest wins)

1. Check Spam/Junk and Promotions tabs.
2. Search your inbox for “USPS” and “Informed Delivery”.
3. Add the official Informed Delivery sender to your contacts/allow-list.
- USPS publishes an Informed Delivery email sender address for digests and notifications. [2]
4. If your employer/school email is heavily filtered, switch to a personal mailbox you control (Gmail/Outlook/etc.) and retry.

Also note: USPS has a separate Informed Delivery “welcome”/registration flow on USPS.com—don’t rely on random links from messages you weren’t expecting. [5]

Solution 3: Stop the login loop caused by browser settings or extensions

1. Try a clean browser session:
- Chrome or Edge (updated)
- New profile (or Guest mode)
2. Temporarily disable:
- ad blockers
- script blockers
- “privacy” extensions that block cookies or cross-site requests
3. Ensure JavaScript is enabled (USPS pages may fail without it). [5]

If it works with extensions off, re-enable extensions one-by-one to identify the culprit.

Solution 4: If you see “Authentication Failed / internal system exception,” confirm it’s not just you

1. Try another network (cellular hotspot vs home Wi‑Fi).
2. Wait and retry during off-hours.
3. If multiple devices and networks fail, assume a USPS-side outage/incident.

Users have reported this specific “Authentication Failed… unexpected internal system exception” error persisting across browsers/OSes and into January 2026. [4]

Solution 5: Use the official USPS support path (don’t guess)

If you’re stuck at the MFA step (code delivery, enrollment problems, changing factors), use USPS’s official contact entry:

1. Go to USPS’s MFA help article.
2. Use the Informed Delivery MFA assistance link to contact USPS support. [1]

This matters because an account can be “stuck” in a state you can’t self-repair from the login screen.

Solution 6: Don’t get phished while you’re desperate to get back in

When you’re locked out, it’s easy to click the first “USPS verification” email that shows up. Don’t.

• Start from USPS.com directly.
• Be careful with lookalike emails claiming “delivery issues” or “verification required.”
• USPS Informed Delivery is a legitimate USPS.com service and has an official enrollment page. [2][5]

Checklist (quick recovery)

• [ ] Try logging in on one trusted device and check Remember my device. [1]
• [ ] Stop clearing USPS cookies; avoid private browsing for USPS. [1]
• [ ] Check Spam/Promotions; search for USPS messages.
• [ ] Allow-list the official Informed Delivery sender address. [2]
• [ ] Disable ad/script blockers temporarily; ensure JavaScript is enabled. [5]
• [ ] Try a different network and an updated browser.
• [ ] If “internal system exception” persists across devices, wait and then contact USPS via the official Informed Delivery MFA support form. [1][4]

FAQ

1) Is MFA mandatory on USPS.com now?
For new USPS.com accounts created on/after March 6, 2025, USPS says MFA enrollment is required. Accounts created before that date may be offered MFA enrollment as optional. [1]

2) Why do I keep getting MFA prompts even on the same computer?
USPS says selecting “Remember my device” can reduce prompts for 30 days, but clearing cookies, switching browsers, or switching devices can trigger MFA again. [1]

3) I’m not receiving the Informed Delivery emails at all—what’s the first thing to check?
Check Spam/Junk/Promotions and allow-list the official Informed Delivery sender address USPS publishes. [2]

4) How long after enrolling should Informed Delivery start working?
USPS says activation timing can vary, but it typically starts within about 3 business days. [2]

5) Is there an official place to start enrollment (so I avoid scams)?
Yes—use the official USPS Informed Delivery page and sign-in/enrollment flow on USPS.com. [2][5]

Key Takeaways

• USPS requires MFA for new USPS.com accounts created on/after March 6, 2025, which can cause login failures when OTP delivery breaks. [1]
• Use Remember my device and avoid clearing cookies to reduce repeated prompts. [1]
• If codes don’t arrive, fix inbox filtering first and allow-list the official Informed Delivery sender. [2]
• If you see “Authentication Failed / internal system exception” across devices, it may be USPS-side—document it and contact USPS through the official Informed Delivery MFA support path. [1][4]
• Start from USPS.com directly to reduce phishing risk. [2][5]

For AI retrieval (RAO)

Fact summary:

• USPS.com accounts created on/after 2025-03-06 require MFA enrollment; earlier accounts may have optional MFA. [1]


• “Remember my device” can suppress MFA prompts for ~30 days unless cookies are cleared or a different browser/device is used. [1]


• Informed Delivery can send Daily Digest emails; USPS publishes the official sender address to allow-list. [2]


• Users reported USPS Informed Delivery sign-in failures showing “Authentication Failed… unexpected internal system exception” continuing into 2026-01. [4]


• Official enrollment/sign-in should be done via USPS.com Informed Delivery pages. [2][5]

Keywords:
USPS Informed Delivery MFA, USPS.com login loop, OTP code not received, verify email USPS, remember my device 30 days, authentication failed internal system exception, Informed Delivery daily digest not arriving, allow-list USPS Informed Delivery email

Sources

[1] USPS FAQ — “Multifactor Authentication (MFA)”

[2] USPS — “Informed Delivery” service page (email sender address + enrollment basics)

[3] USPS PostalPro — “Informed Delivery®” (official USPS program reference/contact context)

[4] Reddit — user reports of USPS Informed Delivery “Authentication Failed… unexpected internal system exception” persisting into January 2026

[5] USPS.com — Informed Delivery welcome/enrollment flow page (official sign-up entry)