AndyO Blog

Saturday, October 31, 2015

Facebook: "You can't post this because it has a blocked link": missing.hwpub.com

After spending at least 6 hours troubleshooting, I've finally discovered why Facebook was blocking URLs to my website.

The problem:

When trying to share or save a URL from my website on Facebook, I saw the error:

The content you're trying to share includes a link that our security systems detected to be unsafe:
http://missing.hwpub.com?ck=ndc96uyh76&et=1
Please remove this link to continue.

The unsafe link (http://missing.hwpub.com) was not on my website, and didn't appear to be called by any scripts.

The Solution

In my case, this error was caused by a missing favicon, a graphic image that is used in the address bar, tabs, and taskbar that provides a visual reminder of the website. According to W3.org, the correct placement of the preferred code is this:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">

<html lang="en-US">

<head profile="http://www.w3.org/2005/10/profile">

<link rel="icon"

      type="image/png"

      href="http://example.com/myicon.png">

What was really strange was that I could share some pages, but not others. I finally noticed (after a lot of research) that the pages I couldn't share didn't include a favicon. Once I added this code, I could share the page.

I'm not sure why having the favicon code is important to sharing on Facebook. As far as I understand, favicons are not required. This looks like a bug in Facebook's system.

Read more about favicons.

Details and troubleshooting

Here's some more detailed information about this issue.

Screenshot of error:

image

Pasting "http://missing.hwpub.com?ck=ndc96uyh76&et=1" resolves to http://dsnextgen.com/?o_id=130920&domainname=missing.hwpub.com

image

Troubleshooting steps:

  1. I wrote to Facebook (per their instructions), and didn't hear back.
  2. I Googled variations on "missing.hwpub.com" and "dsnextgen.com" and couldn't find anything related to Facebook.
  3. I found a lot of search utilities to check URLs, but I couldn't find anything wrong with my site (here's a helpful page: http://www.malwarehelp.org/freeware-open-source-commercial-website-security-tools-services-downloads.html)
  4. Facebook's debugger didn't provide any clues.
  5. I wrote to my website hosting company -- just in case there was a problem on the server -- and they wrote back to say the problem was with Facebook.
  6. Finally, I found this website http://wepawet.iseclab.org/view.php?hash=712d8513ca970d6959b1cbd4bc214bee&t=1374378102&type=js that included the following:

http://missing.hwpub.com/?ck=ndc96uyh76&et=1
http://dsnextgen.com/?o_id=130920&domainname=montecarlodesigns.com%2Ffavicon.ico

When I looked at my website, I saw that the pages I couldn't share didn't have a favicon. As soon as I added a favicon, I could share.

Hope this is helpful for others having this problem.

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posted by AndyO @ 5:09 PM   0 comments links to this post