Title: Error upon plugin activation
Last modified: August 20, 2016

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# Error upon plugin activation

 *  Resolved [Ray56](https://wordpress.org/support/users/ray56/)
 * (@ray56)
 * [13 years, 2 months ago](https://wordpress.org/support/topic/error-upon-plugin-activation/)
 * It seems that I have a plugin conflict. When I activate ITRO, I get the following
   error:
 * Warning: Cannot modify header information – headers already sent by (output started
   at /home/mysite/public_html/myblog/wp-content/plugins/itro-popup/functions/core-
   function.php:9) in /home/mysite/public_html/myblog/wp-content/plugins/itro-popup/
   functions/core-function.php on line 15
 * [http://wordpress.org/extend/plugins/itro-popup/](http://wordpress.org/extend/plugins/itro-popup/)

Viewing 9 replies - 1 through 9 (of 9 total)

 *  Plugin Author [ITRO Team](https://wordpress.org/support/users/itro/)
 * (@itro)
 * [13 years, 2 months ago](https://wordpress.org/support/topic/error-upon-plugin-activation/#post-3532844)
 * We are serching for error in code. For now try to delete and install plugin again.
   
   Have you installed another plugin with Internet Explorer compability? We hope
   to solve the problem as soon as possible!
 *  Plugin Author [ITRO Team](https://wordpress.org/support/users/itro/)
 * (@itro)
 * [13 years, 2 months ago](https://wordpress.org/support/topic/error-upon-plugin-activation/#post-3532956)
 * We have made many tests and no error found. Check your WP version and download
   last plugin version. However we are working for new version so few hours and 
   will be online.
 * For any other problem or suggestions email to: [support.itro@live.it](https://wordpress.org/support/topic/error-upon-plugin-activation/support.itro@live.it?output_format=md)
   
   Thank you!
 *  Thread Starter [Ray56](https://wordpress.org/support/users/ray56/)
 * (@ray56)
 * [13 years, 2 months ago](https://wordpress.org/support/topic/error-upon-plugin-activation/#post-3532982)
 * I’m using the latest WP version.
 * I’ll wait for the new plugin version and give it a try.
 * Thanks for the quick response.
 *  Plugin Author [ITRO Team](https://wordpress.org/support/users/itro/)
 * (@itro)
 * [13 years, 1 month ago](https://wordpress.org/support/topic/error-upon-plugin-activation/#post-3533038)
 * Problem solved?
 *  [elainefogel](https://wordpress.org/support/users/elainefogel/)
 * (@elainefogel)
 * [13 years, 1 month ago](https://wordpress.org/support/topic/error-upon-plugin-activation/#post-3533063)
 * I have the same problem but my error message is:
    Warning: Cannot modify header
   information – headers already sent by (output started at /home/content/e/l/a/
   myWordPresslogin/html/wp-content/plugins/itro-popup/functions/core-function.php:
   64) in /home/content/e/l/a/myWordPresslogin/html/wp-includes/pluggable.php on
   line 876
 *  Plugin Author [ITRO Team](https://wordpress.org/support/users/itro/)
 * (@itro)
 * [13 years, 1 month ago](https://wordpress.org/support/topic/error-upon-plugin-activation/#post-3533064)
 * Hello, can you list us your installed plugins and active theme? Thank you.
 *  Plugin Author [ITRO Team](https://wordpress.org/support/users/itro/)
 * (@itro)
 * [13 years, 1 month ago](https://wordpress.org/support/topic/error-upon-plugin-activation/#post-3533065)
 * Try new release and please report if problem is solved. Thank you.
 *  [cvcasalena](https://wordpress.org/support/users/cvcasalena/)
 * (@cvcasalena)
 * [13 years ago](https://wordpress.org/support/topic/error-upon-plugin-activation/#post-3533074)
 * plugin does not work at all – the basics don’t work let alone trying to customise–
   wasted 3 hours on this
 *  Plugin Author [ITRO Team](https://wordpress.org/support/users/itro/)
 * (@itro)
 * [13 years ago](https://wordpress.org/support/topic/error-upon-plugin-activation/#post-3533075)
 * [@cvcasalena](https://wordpress.org/support/users/cvcasalena/)
    Write in your
   support post, describe your problem, wp version, installed theme and plugins 
   instead of spamming. Thank you.

Viewing 9 replies - 1 through 9 (of 9 total)

The topic ‘Error upon plugin activation’ is closed to new replies.

 * ![](https://ps.w.org/itro-popup/assets/icon-256x256.png?rev=2875939)
 * [ITRO Popup Plugin](https://wordpress.org/plugins/itro-popup/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/itro-popup/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/itro-popup/)
 * [Active Topics](https://wordpress.org/support/plugin/itro-popup/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/itro-popup/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/itro-popup/reviews/)

 * 9 replies
 * 4 participants
 * Last reply from: [ITRO Team](https://wordpress.org/support/users/itro/)
 * Last activity: [13 years ago](https://wordpress.org/support/topic/error-upon-plugin-activation/#post-3533075)
 * Status: resolved