The 404 page appears when a reader tries to access a non-existent page on your knowledge base site - for example, when following a deleted or broken URL. While a browser's default 404 error gives readers no useful path forward, a customized 404 page can acknowledge the error clearly and route readers to the right place through helpful links and navigation buttons.
Once you configure a custom 404 page, you cannot revert to the default. It is recommended to have a custom 404 page to improve the reader experience.
How to customize the 404 page
- Navigate to Settings () > Knowledge base site in the left navigation bar of the Knowledge base portal.
- In the left navigation pane, navigate to Site customization.
- Click the Customize site button.

- From the left dropdown menu, select 404 page.
- Customize the page using one of two options:
- Basic style - Customize the default image, heading, paragraph, and link buttons.
- Custom style - Add custom HTML and CSS. Use the Preview toggle to switch between code view and rendered view.
- Click Save to save without applying immediately, Preview to review, and Publish to make changes live.

Basic style
Image
- Click Image. The Image panel appears.
- Click Change and choose between:
- Default images - Select from available default images and click Save.
- Image - Enter an image URL or upload from your Drive and click Save.
- Set the image alignment (left, center, or right) as needed.

Heading
- Click Heading. The Heading panel appears.
- Enter the desired heading text.
- Select a color from the text color palette.
The default heading will be "404."

Paragraph
- Click Paragraph. The Paragraph panel appears.
- Enter a description to help readers understand the context.
- Select a color from the text color palette.
The default text will be "Oops! Page not found."

Buttons
Add up to three link buttons to guide readers to useful pages.
- Click Buttons.
- Click Add button to create a new button.
- Enter text and URL for each button.
- Click the Delete () icon to remove a button or the Hide () icon to hide it.
- Click Delete at the bottom to remove all buttons.
- Once done, click Save.
Suggested links to include on the 404 page: Home page, a contact form for readers to report broken links, your knowledge base sitemap, and your most popular categories or articles.

Custom style
- Select Custom style and switch between the HTML and CSS sections.
- Update the code as required.
- Turn on the Preview toggle to view the updated page.
- Click Save, then Publish to apply.

Best practices
- Keep the design on-brand - use the same colors and tone as the rest of your knowledge base so readers know they're still in the right place.
- Use friendly, plain language - avoid technical jargon. Acknowledge the error lightly: "It's possible this page has moved or no longer exists."
- Always add at least one button - link back to the home page at minimum. Two or three buttons covering home, documentation, and a contact form gives readers clear next steps.
- Use the 404 page together with redirect rules - customize the 404 page for unavoidable errors, and use Article redirect rules to fix known broken URLs proactively.