Title: Plugin activation = crash
Last modified: July 3, 2020

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# Plugin activation = crash

 *  Resolved [maxpayne1989](https://wordpress.org/support/users/maxpayne1989/)
 * (@maxpayne1989)
 * [5 years, 11 months ago](https://wordpress.org/support/topic/plugin-activation-crash/)
 * Hello,
 * my hoster said I should reinstall WP and my plugins on the server and also do
   a new PHP data base. After I reinstalled everything I wanted to activate the 
   Mailpoet Plugin. I got this notifivations. Who can help me? What do I have to
   do? Thank you =)
 * T already defined in /homepages/13/XXXXX/htdocs/clickandbuilds/XXXX/wp-content/
   plugins/opt-out-for-google-analytics/lib/csstidy/class.csstidy.php on line 41
 * Notice: Constant AT_END already defined in /homepages/13/XXXX/htdocs/clickandbuilds/
   XXXXX/wp-content/plugins/opt-out-for-google-analytics/lib/csstidy/class.csstidy.
   php on line 42
 * Notice: Constant SEL_START already defined in /homepages/13/XXXXX/htdocs/clickandbuilds/
   XXXXX/wp-content/plugins/opt-out-for-google-analytics/lib/csstidy/class.csstidy.
   php on line 43
 * Notice: Constant SEL_END already defined in /homepages/13/XXXXX/htdocs/clickandbuilds/
   XXXXX/wp-content/plugins/opt-out-for-google-analytics/lib/csstidy/class.csstidy.
   php on line 44
 * Notice: Constant PROPERTY already defined in /homepages/13/XXXXX/htdocs/clickandbuilds/
   XXXXX/wp-content/plugins/opt-out-for-google-analytics/lib/csstidy/class.csstidy.
   php on line 45
 * Notice: Constant VALUE already defined in /homepages/13/XXXXX/htdocs/clickandbuilds/
   XXXXX/wp-content/plugins/opt-out-for-google-analytics/lib/csstidy/class.csstidy.
   php on line 46
 * Notice: Constant COMMENT already defined in /homepages/13/XXXXX/htdocs/clickandbuilds/
   XXXXX/wp-content/plugins/opt-out-for-google-analytics/lib/csstidy/class.csstidy.
   php on line 47
 * Notice: Constant IMPORTANT_COMMENT already defined in /homepages/13/XXXX/htdocs/
   clickandbuilds/XXXXX/wp-content/plugins/opt-out-for-google-analytics/lib/csstidy/
   class.csstidy.php on line 48
 * Notice: Constant DEFAULT_AT already defined in /homepages/13/XXXXX/htdocs/clickandbuilds/
   XXXXX/wp-content/plugins/opt-out-for-google-analytics/lib/csstidy/class.csstidy.
   php on line 49
 * Warning: Cannot modify header information – headers already sent by (output started
   at /homepages/13/XXXXX/htdocs/clickandbuilds/XXXX/wp-content/plugins/opt-out-
   for-google-analytics/lib/csstidy/class.csstidy.php:41) in /homepages/13/XXXXX/
   htdocs/clickandbuilds/XXXXX/wp-includes/functions.php on line 6221
 * Warning: Cannot modify header information – headers already sent by (output started
   at /homepages/13/XXXXX/htdocs/clickandbuilds/XXXXX/wp-content/plugins/opt-out-
   for-google-analytics/lib/csstidy/class.csstidy.php:41) in /homepages/13/XXXX/
   htdocs/clickandbuilds/XXXXX/wp-admin/includes/misc.php on line 1282
 * Warning: Cannot modify header information – headers already sent by (output started
   at /homepages/13/XXXX/htdocs/clickandbuilds/XXXX/wp-content/plugins/opt-out-for-
   google-analytics/lib/csstidy/class.csstidy.php:41) in /homepages/13/XXXX/htdocs/
   clickandbuilds/XXXXXX/wp-admin/admin-header.php on line 9

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

 *  [Ian](https://wordpress.org/support/users/starlyth/)
 * (@starlyth)
 * [5 years, 10 months ago](https://wordpress.org/support/topic/plugin-activation-crash/#post-13155966)
 * opt-out-for-google-analytics seems to be the conflict. MailPoet is looking for
   the hooks and opt-out-for-google-analytics is preventing that. Have you deactivated
   or uninstalled opt-out-for-google-analytics prior to activating MailPoet?
 *  [Wysija](https://wordpress.org/support/users/wysija/)
 * (@wysija)
 * [5 years, 8 months ago](https://wordpress.org/support/topic/plugin-activation-crash/#post-13414044)
 * Hello [@maxpayne1989](https://wordpress.org/support/users/maxpayne1989/),
 * As mentioned by Ian, this looks like a plugin conflict. Try the troubleshooting
   steps here: [https://kb.mailpoet.com/article/204-how-to-test-for-plugins-conflict](https://kb.mailpoet.com/article/204-how-to-test-for-plugins-conflict)
 * ​Let us know if you need further assistance.
 * ​Thanks,

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

The topic ‘Plugin activation = crash’ is closed to new replies.

 * ![](https://ps.w.org/mailpoet/assets/icon-256x256.png?rev=3284564)
 * [MailPoet - Newsletters, Email Marketing, and Automation](https://wordpress.org/plugins/mailpoet/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/mailpoet/#faq)
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 * [Unresolved Topics](https://wordpress.org/support/plugin/mailpoet/unresolved/)
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 * 2 replies
 * 3 participants
 * Last reply from: [Wysija](https://wordpress.org/support/users/wysija/)
 * Last activity: [5 years, 8 months ago](https://wordpress.org/support/topic/plugin-activation-crash/#post-13414044)
 * Status: resolved