Title: Optimizer, log errors
Last modified: April 6, 2018

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# Optimizer, log errors

 *  [ceslad](https://wordpress.org/support/users/ceslad/)
 * (@ceslad)
 * [8 years, 1 month ago](https://wordpress.org/support/topic/optimizer-log-errors/)
 * Log errors are popping up every time my site is accessed like this below:
 * PHP Warning: call_user_func_array() expects parameter 1 to be a valid callback,
   function ‘__return_empty_null’ not found or invalid function name in web/wp-includes/
   class-wp-hook.php on line 288
 * Looking for information about this problem with WordPress administrators, I was
   informed that this is due to the lack of updating of the theme.
 * How do I resolve and eliminate these log errors? can anybody help me?
 * Thank you very much in advance.

The topic ‘Optimizer, log errors’ is closed to new replies.

 * ![](https://i0.wp.com/themes.svn.wordpress.org/optimizer/0.7.4/screenshot.png)
 * Optimizer
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 * 0 replies
 * 1 participant
 * Last reply from: [ceslad](https://wordpress.org/support/users/ceslad/)
 * Last activity: [8 years, 1 month ago](https://wordpress.org/support/topic/optimizer-log-errors/)
 * Status: not resolved