I tried to login to Stack Overflow in Firefox via Facebook. After logging into Facebook, I was redirected back to SO with the following error.

Facebook Data Query Failed

What does this error mean and what may have caused it to happen?

  • I'm seeing this on Windows 8.1 with Internet Explorer 11 (11.0.9600.18618), but am able to log in without issue on Google Chrome. – Chad Rexin Mar 27 '17 at 22:20
  • Does this happen every time you try to log in or just intermittently? Sounds like a temporary connectivity issue between us and Facebook. – Adam Lear Mar 28 '17 at 2:32
  • I am having the same problem, happens all the time. IE doesn't work just as firefox. – Momonga-sama Mar 28 '17 at 5:57
  • @Adam I bet it's something to do with the HTTPS changes on SE side, can you ping Nick and try to follow this lead? – Shadow Wizard is Vaccinating Mar 28 '17 at 8:34
  • I am not able to login either. Luckily I had my account logged in on another PC. – Yashas Mar 28 '17 at 8:36
  • You should always keep backup login options for your account. – Yashas Mar 28 '17 at 8:37
  • 1
    @ShadowWizard Nah, login has already been running on HTTPS for ages. ;) Apparently Facebook changed their API. – animuson Mar 28 '17 at 14:10
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    Guess I'll be fixing our Facebook auth path this afternoon. Fun! – Adam Lear Mar 28 '17 at 15:58

We relied on the version of the Facebook API that expired on March 25. The next oldest version changed the response format of the oauth/access_token route from a URL-encoded query string to JSON.

I updated our parsing of the response, and the fix is out in production now.


While it is up to the development team to fix the issue, there is a way out until then. You can create a password for your account using your facebook email address without having to login.

Step 1: Open login page and click on "forget"

enter image description here

Step 2: Enter your facebook email

enter image description here

Step 3: You will receive an email which will allow you to set your password.

enter image description here

  • I'm pretty sure this works only for those who have SE account in addition to Facebook login. – Shadow Wizard is Vaccinating Mar 28 '17 at 12:10
  • The email says "This email address is associated with an account, bu no password is associated with it yet, so it can't be used to log in". How can an account not have a password if it was created? Moreover, the email mentions that I am using my facebook account. It did not mention about my SE account. – Yashas Mar 28 '17 at 12:13
  • One account can have several logins. Facebook is one of them. Google is another. Stack Exchange OpenID is yet another. What you mention in the answer is the last, Stack Exchange OpenID. – Shadow Wizard is Vaccinating Mar 28 '17 at 12:18
  • The email said "As a reminder, you can use any of the following credentials to log in to your account:" and the list had only one entry: my facebook account. Isn't that an indication that I have only one account? As far as I remember, I never created alternate accounts. – Yashas Mar 28 '17 at 12:22
  • And were you really able to set a password for it? I suspect not. – Shadow Wizard is Vaccinating Mar 28 '17 at 12:23
  • Yes I did and I even logged in. I wasn't able to login until now on my daily use PC. I had to use an old ugly annoying computer which had my account already logged in. After setting my password, I was able to login using the email address and the newly created password. – Yashas Mar 28 '17 at 12:24
  • hmm.... so I don't really understand what's going on. Hope this helps other people. :) – Shadow Wizard is Vaccinating Mar 28 '17 at 12:25
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    I'm pretty sure this is just creating an SE OpenID using your already associated FB email (you can't change your actual Facebook password through SE right?)... That of course is a workaround for not being able to log in, it's not a workaround for logging in with Facebook though. – Cai Mar 28 '17 at 14:04
  • Yes, it creates a SE OpenID as an alternate login method. It obviously won't change the facebook password. And yes, this answer does not really answer the question but those who are unable to login can use this workaround until the bug is fixed. – Yashas Mar 28 '17 at 14:06

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