Mystery! Image not showing on Twitter card — but no error in validator


Hi everyone

We’re just implementing Twitter Cards on a blog for a client, but for some reason the image isn’t loading in.

Unless I’m being a complete idiot, we’ve done everything right? I’ve checked the twitter:image meta tag is there and is pointing to the right image.

Only thing I can think of is that the image is served on a different port than the site (don’t ask — previous developers). Is that a restriction? It doesn’t seem to be documented. Could it be a bug?


I can’t make sense of why the image is not showing up, either - you have a robots.txt file which is valid on the domain where the image is hosted. I’m not aware of having a port number included being a restriction with card entity URLs, but I do know that you cannot use a dotted IP syntax in the URLs, so this could be a similar issue.


Weird right?

Yep, I checked the robots.txt on the 8008 port and the 80 port, and there aren’t any rules that would disallow the image.

Is there a way to find out for sure whether images hosted on weird ports are disallowed? Are cross-domain images allowed generally? I assume they must be because of the prevalence of CDNs.


Yeah, I’ve seen cross-domain images working for others, that shouldn’t be the issue.

I’ll have to chat with our cards team to see if they are aware of a limitation here. It may not be a very quick response but I’ll see if there’s anything I can find out.


Appreciate that Andy, many thanks!

If we need to move them to the same port that’s doable. Just need to know.


Possible to give that a shot and see if it addresses the issue? We have a troubleshooting guide here:

We’ve dealt with ASNUM and other issues before, but none specifically calling out the issue you’re seeing.



Can confirm it was the port that was the issue. We’re now serving the images from port 80 - the card validates properly and the image pulls through.

closed #8