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ACE COMBAT 8

ST-3100001 After Time Sync: Compare Connection Scope and Official Notices

For ST-3100001 or disconnections in ACE COMBAT ONLINE after confirming successful Windows time synchronization. A closing game application and failed Windows synchronization need different checks.

Edited by Gemnao Editorial Team (Japanese)Last checked 2026-10-13
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The short answer

Record the phase and time, then check relevant official notices and later updates. Compare another device on the same connection or Ethernet to narrow the scope: one game, this PC or the connection generally. A game-only failure does not prove a server outage, and no published notice does not prove normal service.

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Key facts

Separate the phase
Lobby / match start / mid-match / results screen / application closing
Use dated notices
Match the notice date, affected symptom and subsequent updates to your case
What comparison tells you
Where to investigate next, not a confirmed cause or failed component

Find your symptom

Start with your symptom. Skip steps that do not apply to your setup.

What you seeWhat to checkGo to
Successful synchronization is unverifiedConfirm the Windows sync result firstStep 1
Only this game fails to match or playCompare the affected symptom and environment with official noticesStep 2
Other connections fail or only Wi-Fi is unstableCompare devices and connection methodsStep 3
The cause remains unclear after comparisonGive official support the observations you could verifyStep 4

Fixes, in order

Continue this issue

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Step 1｜Separate the sync result from the failing game phase

Clock synchronization and game connectivity are different results.

Time: About 2 minutes · Risk: low

  1. Record the last successful Windows sync, full game error and event time. A clock that looks right is not enough; verify the sync result first.
  2. Distinguish failure to enter the lobby, failure at match start, a mid-match disconnect, missing results and the application closing. Do not combine different symptoms into one assumed cause.
  3. For the application closing, use launch/crash checks. For a failed sync, return to clock checks. Do not repeatedly enter matches just to reproduce the error.

Windows time synchronization fails — Start here if successful synchronization is unverified.

Step 2｜Match dated official notices to your environment

Check whether the described scope matches what you observe.

Time: About 3 minutes · Risk: low

  1. Check official Steam news and PROJECT_ACES notices for the same mode and phase, followed by resolution or update information. The sources below link to the notices.
  2. The October 9, 2026 notice described ONLINE matchmaking issues in some environments and recommended Windows 11, the officially supported OS, and installation on an SSD. It said details of the release schedule and update contents would be announced once finalized. Check subsequent notices for the current status.
  3. Record your Windows version and whether the game is installed on an SSD. Meeting those conditions does not guarantee a fix, and the notice does not establish one cause for every ST-3100001 occurrence.

Reading notices needs no rollback. A historical notice alone cannot establish a current outage or completed repair; check the dates of later updates.

Step 3｜Compare another device and Ethernet versus Wi-Fi

This narrows the investigation; it does not identify a failed part.

Time: About 5 minutes · Risk: low

  1. Check whether ordinary browsing is also unstable on another device using the same connection. If several devices and services fail, also check official router or internet-provider outage information.
  2. If available on a connection you manage, compare the same PC over Ethernet. Improvement only on Ethernet is a reason to investigate the Wi-Fi path, not proof that the game service is healthy.
  3. If only this game fails, record the game, environment and route as still unresolved. Do not stop a required managed-network VPN or batch router resets, port forwarding and Windows network resets.

Return to your original connection after comparison. A Windows network reset can require VPN and other software to be set up again, so it is not part of this check.

Step 4｜Send the scope and comparison results to the right support team

Leave unknown information marked as unknown.

Time: About 3 minutes · Risk: low

  1. Prepare one record with event time and time zone, mode/phase, exact error, Windows version, installation-drive type, successful sync time and results from the other device and Ethernet comparison.
  2. For a game-only issue, start with official game support; for several devices on one connection, contact the provider/router support; for this PC alone, consult its PC or network support. These are routing choices, not confirmed causes.
  3. After an official update, compare with the original phase and result. Do not publicly expose account names or IP addresses in screenshots or logs; share only what the official support channel requests.

Avoid

  • Do not immediately label a game-only failure a server outage
  • Do not treat the absence of a notice as proof of normal service
  • Do not begin by disabling the firewall, opening arbitrary ports or resetting the network

Important cautions

  • Official notices are dated evidence. An update plan is not confirmation of release or of an individual disconnect’s cause.
  • Even restarting a router interrupts other users. Distinguish restart from factory reset and do not change equipment you do not manage.

FAQ

If websites work, must the game server be at fault?

No. Web browsing and the game use different destinations and conditions. The game environment, account and route may still matter; give official support the phase and comparison results.

Does a stable Ethernet test prove the Wi-Fi hardware is faulty?

No. It is a clue to investigate the Wi-Fi path, not a hardware diagnosis. Record the conditions and follow the router or PC maker’s guidance.

Sources

We checked these official pages and wrote the steps in our own words. Follow the publisher’s page if it has changed.

ACE COMBAT: upcoming update plans and ONLINE matchmaking status, October 9, 2026ACE COMBAT: ST-3100001 and clock checks, September 30, 2026Microsoft: troubleshoot Wi-Fi connection issues in WindowsACE COMBAT 8 (Japanese)Japanese version of this page