Fix Binance Error -1021: Timestamp For This Request Was Ahead Of Server Time (2025)

Updated: 11/29/2025

You launch your trading bot or send an order through the Binance API, and instead of a fill you get a cryptic JSON response, "code":-1021, "msg":"Timestamp for this request was 1000ms ahead of the server's time". This is Binance Error -1021, and it simply means your device or server clock is not closely aligned with Binance's own time, so your signed requests are being rejected as unsafe.[web:4]

The good news is that this is almost never about your API keys being wrong, it is about time drift. If you correct your system time and adjust how your app builds timestamps, the error usually disappears within a minute.[web:6][web:12]

Method 1: Sync Your System Clock To Internet Time

The most common cause of Binance error -1021 is that your computer or server is a few seconds ahead of real time, which makes every signed request look suspicious to the exchange.[web:4][web:6]

Step 1: Check your current time

Look at the clock in your taskbar or menu bar and compare it to a trusted source like time, is or your phone, if your device is even a couple of seconds ahead, that can already trigger -1021 during busy periods.

Step 2: Enable automatic time on Windows

On Windows, open Settings > Time and Language > Date and Time, turn on Set time automatically and Set time zone automatically, then click Sync now if the button is available, wait a few seconds and confirm the time corrected itself.

Step 3: Enable automatic time on macOS

On macOS, open System Settings > General > Date and Time, enable Set time and date automatically, pick an Apple time server or pool, then close the window and give it a minute to update, check that the clock now matches your phone within less than one second.

Step 4: Fix time on a cloud server or VPS

If your trading bot is running on a Linux VPS, you should enable NTP time syncing instead of relying on a manual clock, log in via SSH with a user that has sudo rights, then run the following command to turn on time synchronization.

After a few seconds, run this to verify that NTP is active and your offset is close to zero.

Method 2: Use Binance Server Time In Your App

Even with NTP enabled, your local clock can drift slightly over long periods, especially on low cost VPS providers, to make error -1021 less likely you can periodically ask Binance for their own server time and base your request timestamps on that.[web:12][web:21]

Step 1: Call the server time endpoint

Binance exposes a simple unauthenticated endpoint that returns the current server time in milliseconds, for example you can send a GET request to the following URL from your app or a script.

The response includes a serverTime field, which you can compare to your own clock or directly reuse when signing requests.[web:4]

Step 2: Implement an offset in your code

In many libraries, you can store an offset value like serverTime - localTime, and subtract this offset when creating future timestamps, for example, if your local clock is 6000 ms ahead, you can subtract 6000 from every new timestamp before signing, which keeps you inside Binance's allowed window even if the device drifts slightly.[web:15]

Step 3: Refresh the offset regularly

Time drift accumulates slowly, so your app should re check the server time periodically, for an always on bot, refresh the offset every few minutes or when a timestamp error occurs, for scripts that run once, call the time endpoint at startup and reuse the fresh offset for that single execution.

Method 3: Adjust Your recvWindow And Retries

Binance uses a parameter called recvWindow to decide how long a signed request is considered valid, if you set it too low while your clock is slightly off, you can hit error -1021 even after enabling NTP.[web:4][web:12]

Step 1: Check your current recvWindow

Look at your API client configuration, many libraries default to a recvWindow of 5000 ms or even 1000 ms, which leaves very little room for network latency and clock drift, if you see a very small value here, that is a red flag.

Step 2: Increase recvWindow responsibly

Binance allows recvWindow up to 60000 ms on most endpoints, for most traders, a value between 5000 and 10000 is a good compromise, for example, you might set this in your config.

Do not simply max it out to 60000 unless you really understand the security implication, the larger the window, the longer a leaked signed request stays valid on the network.

Step 3: Implement clean retries after failures

If you hit error -1021 during high load, your bot should log the failure, refresh the server time offset as in Method 2, then rebuild and resend the request once instead of hammering the API in a tight loop, constant retries with a bad timestamp will not fix the problem and may trigger rate limits.