Onebox preview isn't shown for my own blog

Product Support

AI-generated summary

The issue at hand is that onebox preview isn’t being generated for Disane87’s own blog posts on their Discourse instance. However, the onebox preview works fine for the same blog posts on other Discourse instances. Disane87 suspects the issue might be related to their internal network and DNS structure, having tested curl and nslookup with successful results. They have also tried bypassing their DNS server and routing to a public DNS, but to no avail. Heliosurge shared a similar experience with onebox not being generated for links on their Discourse forums, despite previous and later posts from the same domain working as expected. Heliosurge provided an example of a link that isn’t oneboxed on a different Discourse instance.

1

I’m currently setting up Discourse for my community and I’ve encountered a strange issue that isn’t directly related to Discourse itself.

I have a blog, and I want to create a topic for each blog post via the API to enable discussions about the posts. This part works fine. However, the onebox preview for my blog posts isn’t generated:

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But: The onebox preview doesn’t work only on my Discourse instance. It works perfectly on other Discourse instances, like here (this isn’t an ad for my blog; it just shows that it generally works):

The blog is a Ghost blog running on my internal Docker host. I’ve already tested a ping and nslookup to my blog domain, and even a curl works fine in the console of the Discourse Docker container.

Now, I want to track down the issue. I’ve studied the Ruby code for Onebox, but since I’m not an expert in Ruby, it’s a bit of a “black box” for me.

I suspect the issue might be related to my internal network and DNS structure. I use AdGuard Home as my primary DNS, and I can see in the DNS logs that external links are correctly resolved, but my internal links aren’t.

I understand this isn’t a Discourse problem, but I need some hints to track this issue down. What would you recommend I double-check?

2

Update: I already added a test container to the same docker network of discours and checked some stuff.

curl returns the correct content and nslookup resolves to teh correct host.

I also tried to bypass the dns server and routed everything to a public dns. Even that isn’t working.

Any ideas?

3

I am not sure. But have noticed lately at times. One of the Discourse forums(Stable branch) and iirc also on my Tests-passed forum. That sometimes onebox is not being generated for links

Even though previous and later posts from the same domain works as expected. Even with links posted from my Tests-passed forum on the the other Stable one.

4

Here is link to OpenMR running stable with a link to my Tests-passed site. Notice the link is not one boxed.

https://community.openmr.com/t/vr-news-for-2024/41377/168?u=heliosurge