Reverse Proxy intercepting errors can cause the Confluence Page Creation action to freeze

Platform Notice: Data Center Only - This article only applies to Atlassian apps on the Data Center platform.

Note that this KB was created for the Data Center version of the product. Data Center KBs for non-Data-Center-specific features may also work for Server versions of the product, however they have not been tested. Support for Server* products ended on February 15th 2024. If you are running a Server product, you can visit the Atlassian Server end of support announcement to review your migration options.

*Except Fisheye and Crucible

Summary

When attempting to create a new Confluence page, the page editor freezes:

  • if there is a Reverse Proxy configured to intercept errors

  • and when Collaborative Editing is switched ON.

Such an error message can be seen from page editor:

"Something went wrong after loading the editor. Copy your unsaved changes and refresh the page to keep editing."

Environment

  • Confluence version 7.9.0 with Collaborative Editing turned ON

  • NGINX is used as a Reverse Proxy and it is intercepting errors for Confluence and Synchrony, with such directives:

Nginx Configuration

# Server Section in nginx.conf for the Confluence and Synchrony sites server { [...] error_page 404 /404.html; proxy_intercept_errors on; [...] }

Diagnosis

  • Check the Reverse Proxy configuration details for Confluence and Synchrony to confirm the directives used.

Cause

After hitting the Create button in Confluence, such a trace can be seen in the logs:

atlassian-synchrony.log

INFO [async-dispatch-5] [synchrony.middleware.logging] {:request {:remote-addr "127.0.0.1", :uri "/synchrony/v1/data/Synchrony-92cb3632-7851-314b-9957-47c5a6223ec9/confluence-851970", :request-method :post, :query-string "state-at=@head&state-format=type-tagged&rewrite-request=true&cached=true", "x-forwarded-for" "127.0.0.1"}, :response {:status 404}}

ℹ️ Intercepting this 404 can cause the Confluence application to detect that its Synchrony component is unresponsive and freeze.

Solution

  • Remove the lines below from the Reverse Proxy Configuration for Confluence and Synchrony sections.

error_page 404 /404.html; proxy_intercept_errors on;

ℹ️ We do have an existing improvement request for Confluence to handle such situation gracefully under CONFSERVER-55946 - Synchrony - 404 When Creating New Pages

Updated on September 26, 2025

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