# SFTP: java.net.SocketTimeoutException: Read timed out

> The SFTP server's concurrent connection limit is too low for Cascade CMS's parallel publishing. Raise it to at least 25.

URL: https://www.hannonhill.com/cascadecms/latest/articles/content-authoring/publishing/read-timed-out.html
category: Content Authoring
article-type: troubleshooting
content-kind: faq
release-availability: all
tags: publishing, errors
updated: 2026-10-06

You may see the following error when attempting to publish to an SFTP server:

```bash
com.hannonhill.cascade.model.publish.transmit.ShuttleRuntimeException: SFTP error occurred during SFTP Shuttle setup: Session.connect: java.net.SocketTimeoutException: Read timed out
```

This is typically caused by a maximum concurrent connections limit on the SFTP server itself — either total concurrent connections, or connections from a single IP.

To resolve it, increase the connection limit on the target SFTP server. We recommend a minimum of **25** connections, though some organizations need more.

> **Why the limit gets hit**
>
> Cascade CMS publishes in parallel: up to 2 publish jobs from every Site can run at once, and each job uses between 1 and 4 connections depending on how many jobs are running. A limit that looks generous for one Site can be too low across many.