Title: pingbacks / trackbacks / error_log
Last modified: August 18, 2016

---

# pingbacks / trackbacks / error_log

 *  [mikeage](https://wordpress.org/support/users/mikeage/)
 * (@mikeage)
 * [19 years, 7 months ago](https://wordpress.org/support/topic/pingbacks-trackbacks-error_log/)
 * I’m running WP 2.0.4, and having a problem with pingbacks / trackbacks. As I 
   understand it, if I have the options:
 * > Attempt to notify any Weblogs linked to from the article (slows down posting.)
   > 
   > Allow link notifications from other Weblogs (pingbacks and trackbacks.)
 * checked, then I should be able to have a post automatically post a comment to
   any referenced post using pingback. If I manually put the URL of the referenced
   post in the trackback field, it should notify that way.
 * I’m trying to do this with two of my posts, and it’s not working. Instead, I 
   have the following error_log:
    `[16-Sep-2006 15:35:14] PHP Warning: Invalid argument
   supplied for foreach() in /path/to/xmlrpc.php on line 160 [16-Sep-2006 15:35:
   14] PHP Warning: Invalid argument supplied for foreach() in /path/to/xmlrpc.php
   on line 160 [16-Sep-2006 15:35:14] PHP Warning: Cannot modify header information-
   headers already sent by (output started at /path/to/xmlrpc.php:160) in /path/
   to/wp-includes/cl ass-IXR.php on line 357 The last line is repeated 4 times, 
   for lines 357,8,9,and 360
 * Any ideas?

The topic ‘pingbacks / trackbacks / error_log’ is closed to new replies.

## Tags

 * [pingback](https://wordpress.org/support/topic-tag/pingback/)
 * [trackback](https://wordpress.org/support/topic-tag/trackback/)
 * [xml](https://wordpress.org/support/topic-tag/xml/)
 * [xmlrpc](https://wordpress.org/support/topic-tag/xmlrpc/)

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 0 replies
 * 1 participant
 * Last reply from: [mikeage](https://wordpress.org/support/users/mikeage/)
 * Last activity: [19 years, 7 months ago](https://wordpress.org/support/topic/pingbacks-trackbacks-error_log/)
 * Status: not resolved

## Topics

### Topics with no replies

### Non-support topics

### Resolved topics

### Unresolved topics

### All topics