Session Replay Browser Troubleshooting


If you experience unexpected behavior with Datadog Session Replay, use this page to help resolve issues. If you continue to have trouble, contact Datadog Support for further assistance. Regularly update to the latest version of the RUM Browser SDK, as each release contains improvements and fixes.

Session Replay Recorder

Some HTML elements are not visible at replay

Session Replay does not support:

Session Replay requires you to use an HTTPS connection. If you aren’t using a secure connection, the resources time out and you can’t see images and some page elements.

Fonts or images do not render properly

A Session Replay is not a video, but an actual iframe rebuilt based on snapshots of the DOM. The replay thus depends on the various assets of the page: fonts and images.

Assets may not be available at the time of replay for the following reasons:

  • The resource no longer exists. For example, it was part of a previous deployment.
  • The resource is inaccessible. For example, authentication might be required, or the resource might only be accessible from an internal network.
  • The resource is blocked by the browser due to CORS (typically web-fonts).
    • The replay rendered on the sandbox domain and the asset requests are subject to cross-origin security checks by your browser. If the given asset is not authorized for the domain, your browser blocks the request.
    • Allow through the Access-Control-Allow-Origin header for any font or image assets your website depends on to ensure these resources are accessible for the replay. For more information, see Cross Origin Resource Sharing.

CSS rules not properly applied/mouse hover not replayed

Unlike fonts and images, the recorder tries to bundle the various CSS rules applied as part of the recording data, leveraging the CSSStyleSheet interface. If this is not possible, it falls back to recording the links to the CSS files.

For proper mouse hover support, the CSS rules must be accessible through the CSSStyleSheet interface.

If the stylesheets are hosted on a different domain than the web page, access to the CSS rules is subject to cross-origin security checks by the browser, and the browser must be instructed to load the stylesheet leveraging CORS using the crossorigin attribute.

For example, if your application is on the domain and depends on a CSS file on through a link element, the crossorigin attribute should be set to anonymous, unless credentials are required:

<link rel="stylesheet" crossorigin="anonymous"

Additionally, authorize the domain in the This allows the assets file to load the resource by setting the Access-Control-Allow-Origin header.

Further Reading