Unable to render Card preview


Description of issue:

URL affected (must be public):

Troubleshooting steps attempted [note that we will not prioritise posts unless there is evidence of following the troubleshooting guides]:
Card validator says
Unable to render Card preview
INFO: Page fetched successfully
WARN: No metatags found

But as you can see in the preview of this topic I can see card is rendered. And also when i share this link Card is not shown


I got the issue. HTTP header was returning content-type as application/json where it should have been text/html