The answer you entered to the math problem is incorrect.

I have the same problem here, as soon as any captcha-enabled node is loaded, the message appears on the top of the screen. Also, I noticed the following bizarre behaviour:

- I have captcha configured "on" only for anonymous, when I log off to check if it works, I got the message above.
- When I try to log in again, the FIRST attempt to log in ALWAYS fail (but i triple-checked... the password is correct!).
- I have to try to login a second time, before I manage to succeed.
- This behaviour only appears if I attempted to visualise a captcha-enabled node prior to login, otherwise drupal works normally.

My config:
Drupal 5.1
Configuration file Protected
Cron maintenance tasks Last run 3 min 41 sec ago
You can run cron manually.
Database schema Up to date
Drupal core update status Up to date
File system Writable (private download method)
GD library bundled (2.0.28 compatible)
Module update status Up to date
MySQL database 4.1.21
PHP 5.0.5
Unicode library PHP Mbstring Extension
Web server Apache/1.3.37 (Unix) mod_fastcgi/2.4.2 mod_auth_passthrough/1.8 mod_log_bytes/1.2 mod_bwlimited/1.4 FrontPage/5.0.2.2635.SR1.2 mod_ssl/2.8.28 OpenSSL/0.9.7a PHP-CGI/0.1b

The "dev" version of the module does not present that bug, so... maybe importing some code from there might fix the problem...

I have same problem when using 'dev' version.

Really?
Could you describe when it occours better?

I have the same problem, confirmed on two sites running drupal 4.7.
Basically it happens whenever captcha is turned on. When I load a page with a captcha form on it, it is like it thinks you've submitted it already, when really you have not. Please note that this is without even having submitted the form!

What's worse is that a *lot* of people seem to have this problem. Just google for "The answer you entered to the math problem is incorrect." and look at all the embarassed Drupal sites who have this appearing on their pages :[

Including me... http://spatialguru.com/blogchange

Try this thread:
http://drupal.org/node/114387

Take a look at comment #3, it's what I implemented. Add the code to captcha.module, in "function _captcha_validate($captcha_response)" just above "global $user;"

Also getting this problem with the latest dev on v5.1

Should be solved in the 5.x-3.x branch and later.
This thread can probably be closed safely.
Reopen if not.

I am seeing this bug with the math captcha in 5.x-3.1. A possible side effect is that the image and recaptcha captchas always fail.

Please provide more info about you setup:
On which form did you add the CAPTCHA?
Which users are experiencing issues (anonymous/authenticated/...)?
Which browsers (firefox, opera, ie, ...)?
Hosting situation: localhost, shared, ..., some sort of caching setup?
Any other drupal settings or enabled modules that could be relevant?

I am having this problem with firefox, and I only have the captcha enabled for anonymous. I have the captcha enabled on the comment form. I am using 1and1 hosting. Here is the list of modules I am using:

Bbcode 5.x-2.1
Buddylist 5.x-1.1-beta
Calendar 5.x-1.7
CAPTCHA 5.x-3.1
Content Construction Kit (CCK) 5.x-1.6-1
Comment Info 5.x-3.1
Contact Forms 5.x-1.12
Date 5.x-1.x-dev (2008-Jan-22)
Diff 5.x-1.1
FCKeditor - WYSIWYG HTML editor 5.x-2.1-beta2
Filter by node type 5.x-1.x-dev (2007-Jun-18)
Google Analytics 5.x-1.4
Image 5.x-1.6
IMCE 5.x-1.0
Invite 5.x-1.13
Media Field 5.x-1.0
Mediafield Display 5.x-1.0
Meta tags 5.x-1.7
OpenID 5.x-1.1
Privatemsg 5.x-1.8
quicktags 5.x-3.x-dev (2008-Feb-12)
reCAPTCHA 5.x-2.5
Site map 5.x-1.2
Token 5.x-1.10
Update Status 5.x-2.2
Views 5.x-1.6

I hope this helps. Anything else?

Forgot to switch status.

I still get this problem and it is making it impossible to use any captchas on my site. It works on another site. I am not sure what is wrong with this one.

Can you try if CAPTCHA works for authenticated users?
e.g. create a user role without the "skip CAPTCHA" permission, add a user to this role, log in as this user and try to solve a CAPTCHA.

Also make sure you have an entry with uid 0 in your 'users' database table.

(setting the priority back to normal, since it seems to be a problem with your site, not the CAPTCHA module itself, as it works on another site of you)

I unset the ability of an authenticated user to skip the captcha and I still get the same problem. The database says that it has a user with uid 0, but all of the fields besides the uid are blank or null. This is the same on another site that this does work on.

Hmm, so it's not a session/cookie issue.

Blank fields for the uid 0 user is normal.

If it does work normal on the other site: what are the relevant differences between the sites? Are they on the same hosting, multisite setup maybe?

Also, do you have any relevant error/warning messages in your drupal watchdog log?

I get no errors in the log and the site that works is in a multisite configuration with the site that does not work.

I am guessing that this is the result of a module conflict. The only difference I can tell are:

Invite
Invite Stats
Privatemsg
BBcode
Contact Forms
FCKEditor
Filter by node type
IMCE
Meta Tags
OpenID
Qucktags
Buddylist
buddylist invite

I will check to see if I can recreate this problem by enabling one of these modules.

So both are on the same multisite setup. Module conflict is then indeed the most probable cause.

In #11 you mentioned that you are using CAPTCHA on comments. Please also try CAPTCHA on other forms like node creation, contact forms, guestbook, whatever...

Ok, simple fix. Use different public and private keys in recaptcha. When you enter the same key in both fields it doesn't work very well. DUH!

Sorry. Marking as fixed.