Hi, for a few days now, Youtube embedded videos do not show as image preview neither in the composer nor on my home page, which uses the Topics lists plugin.

Victory ! That solution worked: After playing around for a bit, I disabled the “Block onebox on redirect” setting, which fixed the issue for youtu.be links, although I need to rebuilt HTML on old posts.

Check you haven’t run out of space (download remote images threshold). If you have: clear space (./launcher cleanup app etc.) and re-enable download remote images to local (which gets auto-switched OFF)

Hi, Discourse version 3.6.0.beta1-dev safe mode , can’t tell because in safe mode topic list TC is not active so it’s normal the thumbnail does not show Issue already was here before the last upgrade

It’s not that: 14.3 Go available

So for example why my last video and all new ones don”t show a preview image as the previous ones in the same categories were ok? Tutoriels Fusion - Dessein-Tech

Most probably a TC interference because I posted the very same content on my other Discourse site (not the same TCs installed) and the issue did not happened… Will try disabling the TCs one by one :smirking_face:

Well, no, disabling the TCS does not change things… :thinking:

Some news, if I publish in safe-mode I do not have the bug ! Not very practical I must say but the only way, I, as an admin, can publish a Youtube video for now on… Unfortunately for my members… Also if I edit a topic which has generated no preview Youtube image in safe-mode, the preview reappears …

My issue seems very similar to that one: Youtube issues after update

Youtube image preview do not show

Support

nat (Natalie T) September 15, 2025, 5:52pm 2

Hey there, is this happening after an upgrade, or out of the blue? Also what version are you on, and have you tried other videos? Have you tried safe mode?

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Youtube image preview do not show

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