This problem started a couple of months ago, and I cannot understand what causes this. My next move is a complete reinstall of windows. Please help so I can avoid that.
Problem:
On one specific PC Fortnite and Among Us (both using Epic Online Services for login) fail during login/connection setup. Fortnite times out with "Login Timed Out" (sometimes stopping at "Applying preferred region settings" or "Initializing Usability Settings"). Among Us fails with "Unable to get Epic Account ID." The Epic Games Launcher itself sometimes also shows "We are having trouble reconnecting you to Epic Games" after a failed game login attempt.
Key fact: it works perfectly with a VPN enabled. Without VPN, it reliably fails. This has been happening for several months.
What has been tested and ruled out:
General internet/network connectivity — works fine for normal browsing, streaming, etc. Only EOS-based login/authentication is affected.
DNS — confirmed working correctly (tested against 1.1.1.1 and 8.8.8.8, resolved epicgames.com correctly).
Router/mesh network (TP-Link Deco) — no blocking rules, HomeCare/antivirus not the cause; checked client list, no restrictions found.
ISP-level routing to AWS us-east-1 — traceroute showed packet loss shortly after leaving the ISP's international gateway, initially suspected as a peering/routing issue (Embratel/Claro–AWS). However, this was contradicted by other devices working fine.
Ethernet cable and port — cable is new, link speed confirmed at full 1 Gbps via Get-NetAdapter. Switching network profile (Private/Public) made no difference.
IPv6 — disabled entirely, no change.
MTU — identical (1500) on Ethernet and Wi-Fi, ruled out.
CGNAT (shared public IP) — confirmed the connection is behind CGNAT (internal IP in the 100.64.0.0/10 range, different from the real public IP). Initially looked promising as an explanation, but ruled out as the primary cause because:
A Nintendo Switch on the same network (same shared IP) logs into Fortnite without any issue.
A different, separate PC installed fresh on the same network/same shared IP logged into Among Us immediately, no VPN needed.
Windows user profile — created a brand-new local Windows user account on Jo's PC and tested there; same failure occurred, ruling out a corrupted user profile.
Full Epic ecosystem reinstall — uninstalled Fortnite, Epic Games Launcher, and Epic Online Services completely, including attempts to clean up leftover folders/registry/EasyAntiCheat service, then did a fresh reinstall. Same failure persisted. (Note: launcher logged back in automatically post-reinstall, suggesting saved credentials survived in Windows Credential Manager — a cleanup gap, but not the root cause of the connection issue itself.)
Easy Anti-Cheat (EAC) — tested with -noeac launch argument; failure still occurred identically, ruling out EAC as the cause.
Third-party antivirus/security software — none installed on this PC, ruled out.
Background services/startup programs (Clean Boot test) — disabled all non-Microsoft services and startup items, restarted, tested — failure still occurred, ruling this out too.
Wi-Fi vs. Ethernet — originally Wi-Fi worked and wired didn't, pointing to a cable/port issue; but later Wi-Fi also started failing (both now require VPN), which undermined the simple cable/port theory.
Source: r/techsupport · by /u/ejagster