ZettaSend's coordination server became unreachable. Check your internet connection. If your internet is working, the coordination server may be temporarily down — wait and retry. Check this page for service status updates.

When direct P2P connections fail, ZettaSend falls back to a relay server. If even the relay times out:

1. Make sure your firewall or network does not block UDP ports
2. Corporate firewalls may block relay traffic — ask your IT department to whitelist relay connections
3. Try again — temporary relay issues may resolve on their own
4. If persistent, follow the firewall/NAT steps above

This is normal when a direct peer-to-peer connection cannot be established — often due to restrictive NAT configurations that prevent the peers from reaching each other directly. Relay connections are secure (traffic is encrypted end-to-end) but may be slower than a direct P2P link. Where possible, avoid symmetric NAT setups (common on some corporate networks and mobile hotspots) as they make direct connections impossible. Click the relay indicator in the app for tips to improve connection speed.

The other person's app closed, their network dropped, or they intentionally left the transfer. Ask them to rejoin with a fresh invite code.

Generally yes. However, some VPNs block UDP which can prevent direct peer-to-peer connections. If you experience connection issues, try disabling your VPN or configuring it to allow UDP traffic.

ZettaSend uses UDP for peer-to-peer connections. The default port is 39805. You can set a custom fixed port in Settings (range 10000–49000), or leave it empty for a dynamic port.

Possible causes:

Relay mode: transfers through relay are slower than direct P2P. Check if you see the relay indicator.
Bandwidth limits: check your upload/download speed limits in Settings or the Speed Limits window.
Network congestion: other devices on your network may be consuming bandwidth.
Wi-Fi vs Ethernet: wired connections are generally faster and more stable.
Cross-continent transfers: physical distance adds latency.

The file you are trying to send is currently open in another program (e.g., a Word document, a file being written by another app). Close the application using that file and retry.

A file being received conflicts with an open file on the receiver's computer. Close any applications that might be using the destination file or folder and retry.

You created a pending transfer offer, but the files changed before the transfer started. This is a safety feature — ZettaSend detected the change and cancelled to prevent file corruption. Re-select your files and send again.

The transfer is limited to members of the same workspace. You cannot join from outside the workspace. Contact the host if you believe this is an error.

You have used ZettaSend on more than 3 unique devices within 24 hours. Wait for the limit to reset, or use one of your previously authorized devices.

You have reached the daily limit of 100 email invites. Try again tomorrow, or share the invite code manually instead.

The invite code you entered does not exist or has expired. Check the code carefully (codes are case-insensitive). Ask the host for a fresh invite code. Room codes expire after the set time limit (shown as a countdown on the host's screen), or the host may have cancelled the transfer in the meantime.

ZettaSend checks for updates on startup and will attempt to download and install them automatically. If you see this prompt, the auto-update may have been blocked — for example by permissions or a firewall. You can always download the latest version from the Downloads page. We recommend keeping the app up to date for the latest features, performance improvements, and security fixes.

In the app, go to Settings → About ZettaSend. The version number is displayed at the bottom of the screen.

Received files are saved to your Desktop by default. You can change this in Settings under Receiving.

Logs are stored at:

Windows: %LocalAppData%\ZettaSendData\logs\app.log
macOS: ~/Library/Application Support/ZettaSendData/logs/app.log
Linux: ~/.local/share/ZettaSendData/logs/app.log

In the app, go to Settings → See Debug Logs to open the folder. Logs are stored locally and are never sent automatically — your privacy matters. If you contact support, consider attaching the most recent log file to help us diagnose the issue faster.

1. Reproduce the issue
2. Open the debug logs folder (Settings → See Debug Logs)
3. Email the most recent log file along with a description of what happened to [email protected]

Click the "Forgot Password" link on the login page to reset your password. If you still cannot log in, check your email for the verification link we sent when you registered. Contact support if the issue persists.

Go to your Dashboard and click "Manage Your Subscription" to open the Stripe billing portal. From there you can cancel at any time. Your access will remain active until the end of the current billing period.