Title: errors after installing plugin
Last modified: August 30, 2016

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# errors after installing plugin

 *  [nightyard](https://wordpress.org/support/users/nightyard/)
 * (@nightyard)
 * [10 years, 8 months ago](https://wordpress.org/support/topic/errors-after-installing-plugin-1/)
 * Hi, after installing a plugin, whenever I try to save a setting I get this message.
 * In this instance it relates to DecisionTree
 * >  Warning: Missing argument 2 for DecisionTree::on_update_idonated() in /home/
   > iasservicesorg/public_html/wp-content/plugins/sidecar-decision-tree/DecisionTree.
   > php on line 407
   > Warning: Cannot modify header information – headers already sent by (output
   > started at /home/iasservicesorg/public_html/wp-content/plugins/sidecar-decision-
   > tree/DecisionTree.php:407) in /home/iasservicesorg/public_html/wordpress/wp-
   > includes/pluggable.php on line 1179
 * When I try to view the page/tree I created I get a 404

Viewing 2 replies - 1 through 2 (of 2 total)

 *  [Hannah S.L.](https://wordpress.org/support/users/fernashes/)
 * (@fernashes)
 * Automattic Happiness Engineer
 * [10 years, 8 months ago](https://wordpress.org/support/topic/errors-after-installing-plugin-1/#post-6425238)
 * Hi!
 * I suggest you ask on the DecisionTree suppot forums, as they have more in depth
   understanding of the plug-in.
    [https://wordpress.org/plugins/sidecar-decision-tree/](https://wordpress.org/plugins/sidecar-decision-tree/)
 * Hope that helps you out!
 *  Thread Starter [nightyard](https://wordpress.org/support/users/nightyard/)
 * (@nightyard)
 * [10 years, 8 months ago](https://wordpress.org/support/topic/errors-after-installing-plugin-1/#post-6425239)
 * Hi Hannah, I get a missing argument 2 error and a header error with whatever 
   plugin I try to install and use, that is why I am asking in the general troubleshooting

Viewing 2 replies - 1 through 2 (of 2 total)

The topic ‘errors after installing plugin’ is closed to new replies.

## Tags

 * [Cannot modify header information](https://wordpress.org/support/topic-tag/cannot-modify-header-information/)

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 2 replies
 * 2 participants
 * Last reply from: [nightyard](https://wordpress.org/support/users/nightyard/)
 * Last activity: [10 years, 8 months ago](https://wordpress.org/support/topic/errors-after-installing-plugin-1/#post-6425239)
 * Status: not resolved

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