---
layout: post
title: "Fix: macOS 15 Sequoia CUPS printing fails with Validate-Job client-error-not-found"
date: 2026-03-08
tags: [macos, cups, printing, linux]
---

When adding a remote CUPS print server on macOS 15 Sequoia, print jobs may fail immediately with:

```
Validate-Job client-error-not-found
```

## Cause

macOS sends a `Validate-Job` IPP request before submitting the actual print job. If the queue URI is incorrect, the server cannot find the printer and rejects it with this error.

The most common culprit is the **queue name** field when adding the printer via System Settings → Printers & Scanners → Add Printer → IP tab. Leaving it blank or entering just the printer name causes macOS to target the wrong IPP endpoint.

## Fix

When adding the printer, set the **Queue** field to:

```
/printers/<printername>
```

(note `/printers/` prefix, it's not **just the CUPS queue name**)

For example, if your printer is named `office-laser`:

```
/printers/office-laser
```

The full URI should resolve to:

```
ipp://<server>:631/printers/<printername>
```

## Fixing an already-added printer

No need to remove and re-add it. Update the URI in place with `lpadmin`:

```bash
lpadmin -p <printername> -v ipp://<server>:631/printers/<printername>
```

## Verifying the correct URI

You can confirm the printer name and path on the CUPS server with:

```bash
lpstat -v
```

And test the endpoint directly from the Mac before adding the printer:

```bash
ipptool -tv ipp://<server>:631/printers/<printername> get-printer-attributes.test
```
