Fixing a blank screen with the WordPress Mollom Plugin

If you get a white screen after the Mollom Captcha step when trying to add a comment to your blog, then check your PHP errors logs. I was experiencing this problem, and looking into the logs showed the following:

[09-Feb-2009 11:11:53] PHP Fatal error:  Call to undefined function mb_convert_encoding() in /sites/ on line 1371

The mb_convert_encoding() function is part of the PHP mb_string module, so fixing this was relatively easy. As my server was running Centos 5, I could just use yum to install the mb_string functions:

yum install php-mbstring

And then finally, I restarted Apache:

apachectl graceful

5 thoughts on “Fixing a blank screen with the WordPress Mollom Plugin”

  1. Hi Paul! I used the mb_convert_encoding() function to support non-western character sets.

    I’m going to give the plugin a fallback in the upcoming version so you won’t be confronted with a blank screen if you don’t have the plugin installed.


  2. That’s great news – will be a better fix for people who can’t easily install the mb functions.

    I was only made aware of the problem today when one of my blog readers notified me that he couldn’t leave a comment – how did you find my post so fast? 🙂

  3. Thanks Matthias, I actually installed the Multibyte string functions to my server to get it working after my last post, so I can’t test if it has fixed it, but I will update all the same!

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