Facebook Developer: how to solve the “Page requested not found” error when developing a Facebook application

I’m developing a Facebook application for fun in my free time and found the solution to a problem that nagged me for a while.

To develop a Facebook application, you use the Facebook Developer application and create a new application. You can even define a localhost application so that you can debug your application locally. Once all the required parameters are well defined for you application and you begin to test the Facebook integration, you may encounter the following error when following you Canvas Page URL:

FacebookDeveloper2

When this was happening to me, my application wasn’t being called at all by Facebook. If you have a real error in your application, your application should be called and you should be able to debug it or you should be at least getting a 404 error from your server.

The solutionFacebookDeveloper1

With trial and error, incomprehension and a lot of swearing, I finally found out that this is a bug in Facebook and pinpointed exactly how it happens for me.

Ensure that the Canvas Page URL and that your Side Nav URL are both in lowercase! There is something in the Facebook folks code that forbids you to add any uppercase letters to the Canvas Page URL and Side Nav URL. So, to be on the safe side, for every URL defined in your application’s settings in Facebook, use lowercase letters!

By the way, it now looks like this problem is now specific to the Side Nav URL being in lowercase. I am pretty sure that there was a similar Facebook error when the Canvas Page URL was in uppercase.

21 thoughts on “Facebook Developer: how to solve the “Page requested not found” error when developing a Facebook application

  1. Man who would have ever guessed! You Da Man!

    That stumped me everywhich way, maybe 5-8 hours so far … maybe more …

  2. viru

    thanks a lot

  3. Askar

    All my URLs are in lowercase. It still shows that error…I do have a port number in my URL…does that bother Faceborgs ?

  4. Frustrated Developer

    Thank you! I was getting pretty damn frustrated that this was happening to me and it turns out this bug was the source of the problem.

  5. renukadevi

    I am using Iframe for Java aplication for intigrating in Facebook , facing problem while redirecting to the application page from Servlet , the page is occupying full Screen with change of Canvas url to call back url instead rendering in the facebook as an application if any body knows the solution plz reply to it

    and how to post mini feeds in profile page if we use Iframe

  6. Mike

    http://apps.facebook.com/mynextcar/

    My app is this, in setting page, all url is lowercase, but still show this error.

    can you help me?

    holp your help. my account is mike.weib@gmail.com

  7. Man, I’m glad I hadn’t had the same problem. I would have taken me ages to get this solved! 🙂

    Sometimes things can be so easy 🙂

  8. andreas

    thank you so much for that! was already very frustrated that my facebook development enthusiasm could stop so fast 🙂

  9. Wow, thanks for that! I fiddled with that for an hour now.

    I’m really angry about the lost time – how can the developers of facebook be so dumb, and accept an canvas URL that is known not to work…

    I listened around now, and heard only bad things about developing facebook apps…

  10. Roger

    Thanks a ton — I was going partially insane trying to fix that.

  11. Roy

    Jerome! We all owe you about 2-3 hours of our lives. Thanks man!

  12. Roy Truelove

    While we’re on the subject of case sensitivity in Facebook..

    If you :

    Developer Page for your app ->
    DataStoreAdmin ->
    Create Object Type ->
    Type in an object with an uppercase

    The code will silently fail, and just return to the same page. If you change it to lowercase, no problem.

  13. Bilal

    Thanx man, i have wasted many hours of mine in figuring out the problem and then came up with ur post.

    It helped me a lot. 🙂

  14. Pascual

    Thanks for this post Jerome.

    I just spent half a day trying to figure out why my first app could not get accessed by facebook.

    This should appear in bold in their getting started doc (unless I missed it)

  15. Fabulous! You’d think that the facebook guys would at least put that in their getting started guide: http://developers.facebook.com/get_started.php

    I think I’ll clue them in on this.

    Thanks for the post. I think this just proves, in this day and age, if you’ve followed the documentation, and you’re still having troubles, ask the cloud. Someone else has probably had the same issue and knows the solution.

    You’ve been cataloged in StumbledUpon as well. THANK YOU!

    Cheers!

    -J.

  16. PS

    There is now a wiki page specifically dedicated to setting up the example footprints application at:

    http://wiki.developers.facebook.com/index.php/Footprints

  17. myan

    wenever i goto http://apps.facebook.com/myapplication i get the following error

    Server Error in ‘/FacebookApp1’ Application.
    ——————————————————————————–

    HTTP Error 404 – Not Found

  18. Chirayu

    Hey Man!

    great job! i did a lot of swearing too.

  19. ankur

    HOLY SHIT!!! IT WORKS!!!

    FACEBOOK CANT RECOGNISE UPPERCASE CHARACTERS IN FILE !!!!

  20. mon

    I have an error in creating my application.
    I put my canvas url —http://apps.facebook.com/my-application/

    error like
    Error while loading page from myapplication.

    How can I solve this problem?

  21. Tim

    It’s bcoz https is enabled in ur account settings.
    Go to Home > Account Settings > Security > Secure Browsing
    Edit and Disable It

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