If NinjaTrader 8 (NT8) keeps showing login prompts, looping on CAPTCHA, or won't connect to your prop accounts, work through the steps below in order. They go from the quickest, most common fixes to a full session and device reset. Complete all the steps, then reopen NinjaTrader and log in to confirm the issue is resolved.
⚠️ Before You Begin
Make sure NinjaTrader 8 is completely closed before performing any of the steps below.
To confirm it’s fully closed:
Right-click your taskbar → select Task Manager.
End any running processes named NinjaTrader.exe or NinjaTrader 8 (32-bit).
Once confirmed, proceed with the steps below.
Before each step: fully close NinjaTrader
Every step requires NinjaTrader to be completely closed first.
Right-click the taskbar → Task Manager.
End any process named NinjaTrader.exe or NinjaTrader 8 (32-bit).
Step 1 — Sync your system clock
An incorrect system time is the single most common cause of login loops and CAPTCHA failures.
Right-click the clock in the bottom-right of your desktop → Adjust date and time.
Turn Set time automatically ON.
Under "Synchronize your clock," click Sync now.
Wait for "Time was successfully synchronized."
Step 2 — Flush your DNS cache
A stale DNS cache can point NinjaTrader at an outdated authentication server.
Open the Start menu, type
cmd, right-click Command Prompt → Run as administrator.Type the command below and press Enter:
ipconfig /flushdns
Confirm you see "Successfully flushed the DNS Resolver Cache."
Step 3 — Reset your session and device trust
If you're still stuck, the loop is almost always caused by a stale device-trust state. The fix is to clean up your account's trusted devices first, then clear NinjaTrader's local session data, then log in fresh so 2FA can re-establish trust.
Do these in order.
A. Fix device trust in the web dashboard
Sign in to the NinjaTrader web dashboard in your browser. This confirms your credentials are valid.
Enable two-factor authentication (2FA) in your account/security settings if it isn't already on. 2FA is what lets NinjaTrader recognize and trust your device.
Remove old or unfamiliar trusted devices. In the trusted/recognized devices list, delete any stale entries. This clears the bad device-trust records causing the loop.
B. Clear NinjaTrader's local session data
With NinjaTrader fully closed (see top), open your NinjaTrader 8 user folder (usually Documents\NinjaTrader 8\) and:
Delete the
cachefolder. NinjaTrader rebuilds it automatically on next launch.Rename
NinjaTrader.sqliteto something likeNinjaTrader.sqlite.bak. This forces a fresh database on next launch while keeping your old data as a backup you can restore if needed.
C. Restart and log back in
Restart your VPS (if you run NinjaTrader on one) to clear any lingering processes or cached network state. Skip this if you're on a local machine.
Launch NinjaTrader 8 and log in. When the 2FA prompt appears, approve it. This rebuilds a clean device-trust relationship and typically clears the loop.
Still stuck?
If you've completed every step and still can't log in, contact our support team and include:
Which steps you've already tried
Any exact error messages you're seeing
Whether you're on a local machine or a VPS
We're happy to walk through any step with you.
For more, see NinjaTrader's official guide: Common Causes of Login Issues.