UnlockTool Error 400 and 401: authorization errors and how to clear them
Error 400 and Error 401 in UnlockTool are authorization errors: the program could not confirm your access on the server. They are not tied to a specific phone and appear before any operation. In the log they read as Error 400, Error 401, Unauthorized, Login failed or Session expired.
400 vs 401
| Code | Meaning | Common cause |
|---|---|---|
| 400 | bad request | Windows clock, VPN, old version |
| 401 | unauthorized | account data, expired session, PC binding |
Causes by frequency
- wrong Windows time and time zone — the server rejects the request;
- an outdated UnlockTool version;
- network issues: VPN, proxy, ISP blocks;
- the account is bound to another PC;
- antivirus or firewall blocks the connection;
- temporary server maintenance.
Step-by-step fix
- Check the Windows date, time and time zone, enable auto-sync.
- Update UnlockTool to the latest version from unlocktool.net.
- Add the program folder to antivirus and firewall exclusions.
- Try without a VPN; if that fails, try with one.
- Restart the program as administrator.
- If you see a binding message, see the section below.
Error 401 and PC binding
If you recently changed computers, reinstalled Windows or upgraded hardware, the account may still be bound to the old PC, so authorization fails. Reset the binding (Binded PC) through support or your account panel.
Windows time is the top cause of Error 400
Servers verify the request timestamp. If the PC clock has drifted even a few minutes, or the time zone is wrong, the server rejects the request as invalid. Enable automatic time sync and set the correct zone — this fixes a large share of Error 400 cases.
Network and blocks
In some countries or ISPs access is limited, and a VPN helps. In other cases a VPN with a flagged IP causes rejection. If the error appeared suddenly for many users, check the official channels for maintenance.
Reading the message
Session expired means just sign in again. Unauthorized or 401 is an account or binding issue. 400 mentioning time or request points to the Windows clock or network. Save a screenshot; support identifies the cause faster.
If nothing helps
- Sign out and back in.
- Reboot the router to change the route.
- Check for corporate or parental filtering.
- Temporarily disable a third-party firewall.
- Try another connection such as a mobile hotspot.
Not a phone error
Do not confuse 400/401 with phone connection errors. These happen before any device work, so do not change cables or drivers — fix the account, time and network instead.
Real-world example
A technician reinstalled Windows and got Error 401 on every login. The account was still bound to the old system and the clock had drifted. After time sync and a binding reset through support, login was restored.
What not to do
- do not enter account data into third-party activators;
- do not install chat builds instead of the official version;
- do not set the time by hand — enable sync.
Glossary
- Authorization — access confirmation on the server.
- Binded PC — account tied to one computer.
- Session — a temporary grant after sign-in.
If you need access
If your own licence is unavailable, UnlockTool rental is delivered automatically and already tied to a working account. Login arrives right after payment.
Bottom line
Error 400 and 401 are almost always the Windows clock, an old version, the network or PC binding. Sync the time, update, check the network and the binding — in most cases that is enough.
A corporate network example
In a shop inside a mall, UnlockTool gave Error 400 for every technician. The cause was traffic filtering on the shared network. A mobile hotspot fixed it at once. Sometimes the problem is the network the PC sits in, not the program.
Prevention
- keep time sync enabled;
- update the program as soon as a version ships;
- do not change hardware without resetting the binding first;
- keep the program folder in antivirus exclusions permanently.
Keep a quick reference
Pin a short note at the bench: 400 means check time, version and network; 401 means check the account and PC binding. That way you tell an account problem from a phone problem instantly.
Working efficiently
Treat 400/401 as account-and-network problems, never as a reason to re-check the phone. Most lost time here comes from technicians swapping cables and drivers when the fix was a clock, a version or a PC binding.
FAQ
What does Error 401 mean?
The server rejected authorization: wrong data, an expired session or a PC-binding problem.
Is Error 400 a ban?
No, it is usually a bad request from the Windows clock, VPN or an outdated version.
Does reinstalling help?
Sometimes, a clean install of the latest version clears conflicts.
Do I need a VPN?
In some networks yes, in others it causes rejection; try both.
Why after a Windows update?
The clock or time zone may have drifted, or network settings changed.
Only on the work PC?
Check corporate filtering, proxy and firewall, time sync and antivirus exclusions.