Open graph image not displaying unsupported media type

Hello, I’m trying to figure out why an open graph image isn’t getting displayed on Slack as a preview. I’ve tested it on all other social platforms and it works fine. Facebook’s debugger tool works fine, but iframely provides and error of unsupported media type.


Could someone provide some quick advice on this? @codinghorror @sam

That’s the error, then… I usually use for testing.

@codinghorror that’s what I was trying to explain. It doesn’t make it that far.

It reports error 417 - unsupported media type.

No repro, works fine on my instance (self-hosted)?

I’m hosting on Linode. Had to install the aufs module. Here’s what I followed:

On Facebook’s tool it works perfect. I only can’t figure out why the image doesn’t show on Slack.

Maybe your image is too big? It’s 1200x1200 which is huge for a thumbnail.

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OG Images are often very large. Most recommend 1200 x 630 but other sources say 1200 x 1200 because certain platforms have a square ratio. I contacted Slack to understand why it doesn’t show up, but that still doesn’t explain why Iframely is having issues with it.

@codinghorror I don’t understand why the need to debug an image that’s added through the admin panel. No code has been modified other than logo size on mobile using CSS. I almost think it has something to do with the web server or possibly CloudFlare settings.

The wonderful support team at Slack helped me solve the issue. It was CloudFlare’s hotlinking setting blocking access. Hope this thread helps someone else. Thanks to all who helped me with this. Loving Discourse!