The following errors may occur during a deployment via FTP: 

```
Error communicating with your server: 426 Transfer aborted. Interrupted system call.
```

```
Error communicating with your server: 426 Failure reading network stream.
```

Which suggest the connection hasn't correctly completed or has been unexpectedly closed by the destination server. Primarily this may be caused by a loss of connection between DeployHQ and your server, and the server's FTP logs should be checked. 

Please also ensure that our [IP ranges](https://www.deployhq.com/support/faq/our-ip-ranges) are allowed through the server's firewall. It can help to switch between active and passive mode in your DeployHQ server setup.