The OTP password window shown when logging in to the game
The OTP window at game login · Image: NTTGame
Source / rights
Image / usage information: Knight Online — Mgame / NTTGame. · Image source ↗

Knight Online errors: symptom, cause and fix

Knight Online error table (fixes from NTTGame sources)
Error / symptomLikely causeWhat to do
Game won't start, a message on the login screen, or constant DCs Maintenance, full server, connection or region block; the message tells you which What each message means is in the not starting / DC guide
Downloaded it but it won't open or patch Servers are down for maintenance (no updates during maintenance), the launcher can't finish updating, or the client is outdated If it is maintenance, wait it out; otherwise see the launcher section of the download and install guide
"Extract failed" while patching or installing Patching while the game is running; a file in the patch (e.g. KnightOnline.exe) is in use and can't be overwritten Close every game window and run the launcher again
"There is no active OTP/ICS on your account" ICS not set up, or not activated for Knight Online on the portal OTP setup guide: setup and portal activation
"Access Restricted" (server open to ICS-registered users only) No ICS registration on the account The steps in the OTP setup guide
OTP is not active, OTP code rejected OTP or time sync problem OTP error guide
AnyOTP is blocked Wrong AnyOTP password entries Open a support ticket
ICS won't accept your phone number The number is already on 3 accounts (May 13, 2026 rule) Continue with a number never used for ICS
No OTP ID or auth code The setup text was deleted or lost otp.nttgame.com > My ICS > Resend OTP ID & Auth Code
New phone, OTP not arriving ICS still has the old number My ICS > Change Mobile (5 NPoints, once per 24 hours); ticket if the old number is gone
Can't trade No SMS verification on the account Portal > My Account > Game Services > SMS Verification (code valid 600 seconds)
Can't join or register on a new server OTP inactive, phone not verified, server changes used up, or registration paused New server guide and OTP setup guide
"Duplicate IP is detected" More than one character from the same IP trying to enter an event Event messages in the not starting / DC guide
Bought NPoints but they didn't arrive Payment verification can take a few days Don't pay again or open a chargeback; ticket if it drags on
Bought the wrong item, want a refund Store purchases aren't refunded No refunds; double-check before buying
Forgot my password or ID Lost login details Use "Forgot your password?" or "Forgot your ID?" on the sign-in page
Password, ID or VIP Key email never arrives Delivery problem to Hotmail, Outlook and Live addresses (NTTGame, February 24, 2026) NTTGame is looking into it; open a ticket if the step can't be finished
Disconnects while playing from abroad NTTGame reported DDoS attacks from abroad in March 2025 Follow the notices; for codes like 10060/10053 see the connection errors guide, then open a ticket if it continues
Forgot the security key or VIP vault key Key lost Portal > My Account > Game Services > Knight Online: a reset link goes to your email
Account stolen Password or email compromised Change your email and password right away and open a ticket
Got banned Rule violation detected Banned account guide (the official appeal route)

Detailed guides by error code

If the screen shows an error code or a specific message, jump to that error's own guide below; SteamKO errors are listed here too.

Knight Online won't start

The login screen message tells you why: maintenance, a full server, the connection or an ICS region restriction. What each message means and what to do is in the not starting / DC guide, along with the fix for the game not opening after the DirectX 11 update.

Knight Online won't patch, or won't open after downloading

NTTGame's install guide says launcher.exe updates the game on its own when a new version is out. If the update doesn't finish or the client won't open, follow the download and install guide. Only download the client from NTTGame's official download page. If patching stops with "extract failed", the game is usually still open; see the next section.

If the patch won't download at all, check for maintenance first: while the servers are down for maintenance, the launcher can't get updates either. Wait for maintenance to end and open the launcher again; maintenance times are in the not starting / DC guide.

Knight Online "extract failed" error

Extract failed usually shows up when the launcher tries to patch while the game is still running. If the patch includes a file that's in use, like KnightOnline.exe, the launcher can't overwrite it and the patch stops halfway.

  1. Close every Knight Online window, all of them if you run more than one client.
  2. If the window is gone but patching still fails, check Task Manager for a leftover KnightOnline.exe and end it.
  3. Run the launcher again; it installs the update itself when there is a new version.

If the patch still won't download or stops halfway with the game closed, the servers may be down for maintenance: they're offline during maintenance, so no updates come through. Wait for it to end and open the launcher again.

The installer also asks you to close other applications before continuing. If you still get extract failed with the game closed and no maintenance on, reinstall the client from NTTGame's official download page, and if that doesn't help, open a support ticket with a screenshot of the error.

"There is no active OTP/ICS on your account"

This means ICS isn't set up or isn't switched on for Knight Online. Finish setup at otp.nttgame.com, then activate ICS for Knight Online on the NTTGame portal under My Account > Overview > Game Services. The full steps are in the OTP setup guide.

Knight Online trading won't unlock

Trading needs SMS verification on the account. On the portal go to My Account > Overview > Game Services > SMS Verification, enter your number and type in the code within 600 seconds, then click Verify. One number works for up to 3 accounts.

Can't join a new Knight Online server

For the 2022 new servers, NTTGame listed these blockers: without active OTP/ICS the register button showed a warning, registration needed an SMS code to your phone, and one phone number could only register one account. Once you made a character on a new server you couldn't switch; the number of server changes allowed before that is given as two in the November 4, 2022 notice and one in the November 17 notice.

On December 12, 2022 registration on Agartha and Zero was paused temporarily to balance the servers. If a new server opens, the requirements will be in its announcement.

Forgot your password, security key or VIP vault key

  • Account password: click "Forgot your password?" on the nttgame.com sign-in page and enter your ID and registered email; you get a temporary password, change it as soon as you log in.
  • Security key: on the portal, My Account > Overview > Game Services > Knight Online > Reset Security Key; the reset link goes to your email.
  • VIP vault key: log out of the game first, then open the VIP KEY section in the same place; reset it from the email link and create a new 4-digit key in game at Inn Hostess > Use VIP Storage > padlock icon.

If the email never comes, check your address: on February 24, 2026 NTTGame said mail to Microsoft addresses such as Hotmail, Outlook and Live may not be delivered, so VIP Key, Forgot ID and password resets may not complete. The sign-up form also temporarily blocks those domains.

NPoints didn't arrive, or you bought the wrong item

NPoints can take a few days to arrive because of payment verification; don't pay again or open a chargeback in the meantime. PUS and web shop purchases aren't refundable; details are in the Power Up Store guide.

Official support: where do you open a ticket?

NTTGame support lives at support.nttgame.com. To open a ticket you log in with your portal account (Login With Portal ID); without logging in you can still read the Knowledgebase articles on ICS, SMS, NPoints and accounts. NTTGame says it treats logins through proxy IPs as suspicious, so try your normal connection first if you have connection trouble.

Playing from abroad? In March 2025 NTTGame reported heavy DDoS attacks from abroad on its game and web servers and said they were causing connection problems mainly for players outside the country. Region blocks and VPNs are covered in the not starting / DC guide.

Source · support.nttgame.comNTTGame — Submit a support ticket

Source · support.nttgame.comNTTGame — Knowledgebase

Frequently asked questions

Where do you report a Knight Online error?
Log in to support.nttgame.com with your portal account and open a ticket. Include the exact error text and a screenshot so it gets solved faster.
I have OTP but can't log in. Why?
ICS may not be activated for Knight Online on the portal, or AnyOTP's clock may be off. Activate it under Game Services first, then check the OTP error guide.
Why is trading locked in Knight Online?
Without SMS verification on the account, trading stays locked. Complete Game Services > SMS Verification on the portal.
What causes extract failed in Knight Online?
Usually patching while the game is running: files in the patch, like KnightOnline.exe, are in use and can't be overwritten. Close every game window and run the launcher again.
Why won't Knight Online patch?
If the servers are down for maintenance, the launcher can't get updates; wait for maintenance to end. If there's no maintenance, make sure the game is fully closed and run the launcher again.
Can I get a refund on a PUS purchase?
No, in-game store purchases aren't refunded for any reason, and NPoints can't be refunded once the payment goes through.

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