Title: debug.log msg Last modified: December 2, 2022 --- # debug.log msg * Resolved [jsm06278](https://wordpress.org/support/users/jsm06278/) * (@jsm06278) * [3 years, 4 months ago](https://wordpress.org/support/topic/debug-log-msg/) * Since Nov 28 the following message has been appearing in our debug.log file at regular intervals (3-4 minutes). * ``` [28-Nov-2022 20:38:26 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 20:40:26 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 20:41:30 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 20:44:26 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 20:45:29 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 20:47:28 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 20:48:30 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 20:51:27 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 20:52:26 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 20:54:26 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 20:55:31 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 20:58:26 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 20:59:27 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 21:01:32 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 21:02:26 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 21:05:27 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 21:06:27 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 [28-Nov-2022 21:08:26 UTC] PHP Warning: Cannot modify header information - headers already sent in /XXX/YYYYY/public_html/wp-content/plugins/mailpoet/lib/Util/Cookies.php on line 35 ``` * I’m not sure if it actually affects MailPoet operation but it might. Any thoughts on how to resolve this? * Thank you! Viewing 2 replies - 1 through 2 (of 2 total) * Plugin Support [Ojoma a11n](https://wordpress.org/support/users/geraltrivia/) * (@geraltrivia) * [3 years, 3 months ago](https://wordpress.org/support/topic/debug-log-msg/#post-16264521) * Hello there [@jsm06278](https://wordpress.org/support/users/jsm06278/) , * Thank you for reaching out to us. * The PHP Warning: Cannot modify header information – headers already error is strange as it is most often caused by issues with faulty code in a plugin file( i.e. whitespace where it shouldn’t be). I’m not seeing other reports of this from other MailPoet users though, which would indicate it is specific to something on your site. * As a first step, reinstalling a fresh copy of the plugin should help ensure there are no files that got corrupted when updating. I’d recommend taking a full backup of the site first, just in case. After that you can download a copy of the plugin here: [https://wordpress.org/plugins/mailpoet/](https://wordpress.org/plugins/mailpoet/) * Then we have a guide for re-installing via FTP here: [https://kb.mailpoet.com/article/258-re-installing-updating-the-plugin-via-ftp](https://kb.mailpoet.com/article/258-re-installing-updating-the-plugin-via-ftp) * If you are still seeing the same issue after reinstalling, then another good step to try would be a conflict test. Testing to see if the issue occurs with only MailPoet active, and a default theme like Twenty Twenty would help to rule out any conflicts. We have a guide for conflict testing available 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) * Please let me know how that goes, or if you have any questions! * Have a great day. * Plugin Support [slash1andy](https://wordpress.org/support/users/slash1andy/) * (@slash1andy) * Automattic Happiness Engineer * [3 years, 3 months ago](https://wordpress.org/support/topic/debug-log-msg/#post-16310604) * We haven’t heard back from you in a while, so I’m going to mark this as resolved– we’ll be here if and/or when you are ready to continue. Viewing 2 replies - 1 through 2 (of 2 total) The topic ‘debug.log msg’ 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) * [Support Threads](https://wordpress.org/support/plugin/mailpoet/) * [Active Topics](https://wordpress.org/support/plugin/mailpoet/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/mailpoet/unresolved/) * [Reviews](https://wordpress.org/support/plugin/mailpoet/reviews/) ## Tags * [modify header information](https://wordpress.org/support/topic-tag/modify-header-information/) * [PHP Warning](https://wordpress.org/support/topic-tag/php-warning/) * 2 replies * 3 participants * Last reply from: [slash1andy](https://wordpress.org/support/users/slash1andy/) * Last activity: [3 years, 3 months ago](https://wordpress.org/support/topic/debug-log-msg/#post-16310604) * Status: resolved