Ace Combat 8 Online Errors: ST-3100001
ST-3100001 means communication with the game server was lost. On Windows, the first official check is to synchronize your clock, then test again. It is not proof that your account is banned, and it is not the same problem as a crash to desktop.
Windows: synchronize, restart, test
- 1
Exit the failed online session
Note the exact error code before closing the game. If the whole application closed or an Unreal error box appeared, use the crash troubleshooting page instead of treating it as a network-only failure. - 2
Open Date & time
In Windows Settings, choose Time & language, then Date & time. Check the clock and time zone. Enable automatic time if appropriate for your PC. - 3
Choose Sync now
Use the clock synchronization control and check that Windows reports a successful sync. If Windows cannot sync, fix that system issue before expecting the game to use a corrected clock. - 4
Launch from Steam and try again
Reopen the game and return to Ace Combat Online. Test once after the change. If the same error returns, record it; repeated retries alone do not identify whether the failure is local or server-side.
Match the symptom before trying a fix
| What happened? | What to check | Next step |
|---|---|---|
| ST-3100001, game still open | Server communication was lost. | Synchronize the Windows clock, then retest. If it persists, record platform and exact code. |
| Game closes or shows UE live error 01 | Client stability, driver, free storage and virtual memory. | Follow the PC crash checks; time sync does not fix every client crash. |
| ST-3200003 on Linux or Steam Deck | Online anti-cheat support is a separate limitation. | Read the Linux online restriction. A working campaign does not establish online compatibility. |
| WP-112001006 or WP-112003008 at login | Players report being unable to enter online, sometimes after previously playing successfully. | Record the code and whether the lobby or store opens. There is no established general fix for these reports; do not assume the ST-3100001 time-sync step resolves them. |
| A matchmaking restriction appears | The restriction message, not just the preceding disconnect. | Follow the displayed restriction and contact support with the details. Avoid assuming clock sync clears it. |
| Lobby or character screen stays at 0% | A loading problem without the same confirmed diagnosis. | Capture the screen and report the stage where loading stops. Do not delete your save to try to clear an online state. |
If time sync did not solve it
Keep the exact code, platform, when the error occurs, and whether a restriction message follows. Note whether you can reach the air base but fail when a sortie starts, or cannot enter online at all. Those are more useful details than simply saying multiplayer is broken.
For general connection diagnosis, check whether other online services work on the same connection and whether Windows successfully synchronized. These checks narrow the problem; they are not a guaranteed AC8 fix. Reinstalling the game or changing your GPU does not follow from ST-3100001 alone.
On PS5 and Xbox, the Windows clock instructions do not apply. Record the console's code and the point of failure, then use your regional Bandai Namco support portal. Never include passwords or activation codes in a public bug report.
What carries between campaign and online?
Ace Combat Online has separate progression and save data. Campaign aircraft unlocks do not automatically give you the same online roster. The multiplayer mode guide explains co-op, crossplay and sortie types; Ace Pass rewards covers the separate reward track. For a stick that works in menus but not in flight, use the HOTAS detection and binding checks.