Facebook OAUTH error

I am trying to authenticate my application using Facebook PHP SDK. It is working fine, but for some users it will show the following users

{
   "error": {
      "type": "OAuthException",
      "message": "An unexpected error has occurred. Please retry your request later."
   }
}

It is creating a access token. But开发者_如何学C still it shows the errors.

I found the problem in my case. The users that we receiving the error had activated https for their accounts and my application didn't have SSL activated. So I had to make sure that my app would work properly also over https.

In Facebook you can activate secure browsing by going to your account and (on the left) selecting "security" option.

It took many hours to find the reason and it was found by coincidence when I tried a simplified app that unlike the big one it complained about SSL. But it was the app who complained, Facebook kept sending a really vague error.