What Is ERR_CONNECTION_ABORTED and How Do You Fix It?

ERR_CONNECTION_ABORTED is an error showing that the connection between the browser and the server was cut off midway during data transfer. Chrome then shows the code ERR_CONNECTION_ABORTED on the “This site can’t be reached” screen. The error sometimes appears on every site, and sometimes only on one site or while uploading files. In this guide we explain what the error means, its causes, and the fixes for visitors and site owners.

What Does ERR_CONNECTION_ABORTED Mean?

In Chrome’s list of network errors, this code describes a connection that was aborted because no acknowledgement (ACK) came back for data that was sent. In other words, the connection was established and data started to flow, but the transfer could not finish because of a problem in between. This is different from ERR_CONNECTION_CLOSED, where the server closes the connection cleanly, and ERR_CONNECTION_RESET, where it is reset with an RST packet.

Causes of the Error

• Unstable internet connection: Packet loss and drops leave the transfer unfinished.
• Security software or firewall: Antivirus software and firewalls that inspect traffic can abort the connection.
• VPN or proxy: A VPN or proxy that does not carry traffic properly can cut the transfer.
• MTU mismatch: Because of a packet size limit on the network, large packets may not reach the target; small pages then open while large pages and file uploads fail.
• Server limits: The server can cut off uploads that exceed the allowed size or requests that take too long.
• Browser extensions: Extensions that modify requests can break the connection.

How to Fix It as a Visitor

1. Try another network: Open the site on your phone over mobile data. If it opens, the problem is on your network.
2. Restart your router: Turn it off and on again after 30 seconds.
3. Test your security software: Briefly turn off the antivirus web protection and try again; if that solves it, add the site or Chrome to the exceptions.
4. Turn off VPN and proxy: On Windows, check Settings > Network & Internet > Proxy.
5. Turn off extensions: Open the site in an incognito window; if it opens, turn extensions off one by one.
6. Reset network settings: Open Command Prompt as administrator, run the commands below and restart the computer.

netsh winsock reset
netsh int ip reset
ipconfig /flushdns

If small pages open but large pages do not, you can test for an MTU problem with this command: ping -f -l 1472 example.com. If you get “Packet needs to be fragmented”, lower the value to find the largest size that gets through; in that case the MTU value in the router or VPN settings may need to be lowered.

How to Fix It as a Site Owner

1. Check upload limits: If the error appears while uploading files, review upload_max_filesize and post_max_size in PHP and client_max_body_size in Nginx.
2. Review timeout settings: Long-running operations can be cut off by web server or PHP timeouts.
3. Check security rules: WAF, ModSecurity or CDN rules can cut certain requests short.
4. Look at the error logs: Web server and application error logs show why requests were cut off.

For similar cases where the connection is closed or reset, see our guides on ERR_CONNECTION_CLOSED and ERR_CONNECTION_RESET, and for cases where the server does not answer at all, see ERR_CONNECTION_TIMED_OUT.

Conclusion

ERR_CONNECTION_ABORTED shows that the connection was cut off midway during data transfer. As a visitor, checking the network, security software, VPN and extensions is usually enough. If the error appears while uploading files or only on your own site, review the server’s upload limits, timeouts and security rules.