I’ve added facebook comments on a wordpress blog like the one here on FlashSolver, it’s working fine and everything but on some pages it displays the comment box and under it it gives a warning url is unreachable and it doesn’t show the moderator’s setting either when it shows that warning.
so i was a bit baffled and annoyed, tried to find a solution and read forums but each person has a different answer and non of them worked for that blog. after digging around for a long time (a week) I’ve figured out the problem of the issue in the blog, lazy load plugin was installed and when facebook try to read the website it reads it partially so it cause some sort of an error, when i disabled it everything just went back to normal and worked fine.
Here is the facebook explanation when i was tracking the error that helped in spotting the cause of the problem.
Partial Content The server is delivering only part of the resource due to a range header sent by the client. The range header is used by tools like wget to enable resuming of interrupted downloads, or split a download into multiple simultaneous streams.
here is the reference for it HTTP response status codes
Hope it helps!