YouTube Embed block not working on Safari

[alessandrolioce]

When embedding a YouTube video using the YouTube Embed block in the Block Editor, Safari (version 26.1 on macOS 26.1) displays the following error within the embedded player:

Error 153
Video player configuration error

The same embed works correctly in Firefox 146 and Chrome 143 on macOS.

According to the official YouTube documentation:
​https://support.google.com/youtube/answer/171780?hl=en#zippy=%2Cprovide-a-http-referer-header-to-enable-video-playback

YouTube requires the embedded player to receive a valid HTTP Referer header.
If the Referer is missing, playback may be blocked and Error 153 is displayed.

Safari appears to be omitting the Referer in the embed request due to YouTube blocking, causing the issue.

The issue occurs in the admin editor, but not in the frontend.

Steps to reproduce the problem:

• Log in to the WordPress admin with Safari
• Create a new post using the block editor
• Add the YouTube Embed block
• Enter the URL ​https://www.youtube.com/watch?v=182f6dTagkU
• Press the Embed button
• The player displays error 153

Expected Behavior
The video preview should display correctly within the YouTube block.

Test Environment

• WordPress: 6.9
• Theme: Twenty Twenty-Five v1.4
• Active Plugins: None
• Safari: 26.1
• macOS: 26.1

Curl request without referrer

curl "https://www.youtube.com/embed/182f6dTagkU?feature=oembed" \
  -X GET \
  -H "User-Agent: Mozilla/5.0" \
  -H "Accept-Language: en-US,it;q=0.9" \
  -H "Accept: text/html,*/*" \
| grep --color=always -E "Video player configuration error|PLAYABILITY_ERROR_CODE_EMBEDDER_IDENTITY_MISSING_REFERRER|Error 153"

[alessandrolioce]

Curl response

[alessandrolioce]

Error 153

[westonruter]

Thanks for reporting this issue. It's currently being tracked upstream in Gutenberg: ​https://github.com/WordPress/gutenberg/issues/73288