Title: PHP errors Last modified: January 23, 2022 --- # PHP errors * Resolved [Seath](https://wordpress.org/support/users/seath/) * (@seath) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-errors-262/) * Hello The plugin is creating this PHP Error * `Warning: Cannot modify header information - headers already sent by (output started at /wp-cron.php:28) in /wp-includes/functions.php on line 6712` * I have 2 test sites with exactly the same installation of plugins. And only the site with this plugin is producing the error. Reason for doing this was because my production site error log is getting filed with this error and I wanted to test what plugin is doing that. * I am on php 8 and wordpress 5.8.3 * Thank you. Viewing 10 replies - 1 through 10 (of 10 total) * Plugin Support [vupdraft](https://wordpress.org/support/users/vupdraft/) * (@vupdraft) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-errors-262/#post-15286040) * Hi, * The issue appears to be with your functions.php file. The usual cause for this type of error is whitespace * If the faulty file has whitespaces, the easiest way to solve the issue is to manually edit the issue via an FTP or a File Manager. You can start from line 6712 (the one that is mentioned in the error message), then look through the rest of the file for any unnecessary spaces. * Make sure to pay attention to the beginning and end of PHP tags. There should be no spaces before the tag and file’s last line of the code. * Most text editors can remove whitespaces automatically. Alternatively, you can use online whitespace removal tools like TextFixer and Code Beautify to do the job for you.` * Thread Starter [Seath](https://wordpress.org/support/users/seath/) * (@seath) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-errors-262/#post-15286241) * Thank you for your responds. * I am not sure if you noticed but those are WordPress files not mine. * wp-cron.php functions.php * so I can’t edit them. * Also, as I have mention I have two test sites set up both are exact clones of each other with the default theme Twenty Twenty-One. The only difference is that one has your plugin enabled and that is where I get the error. * I do not have any custom function on those test sites. * Please advise. Thank you * Plugin Contributor [Prashant Baldha](https://wordpress.org/support/users/pmbaldha/) * (@pmbaldha) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-errors-262/#post-15287603) * [@seath](https://wordpress.org/support/users/seath/) [@vupdraft](https://wordpress.org/support/users/vupdraft/) I have tested the All in One WP Security & Firewall plugin version 4.4.10 (The latest released version released on 21, January 2022) and found no error with PHP 8.0. Are you using the latest version of the All in One WP Security & Firewall plugin? * Plugin Support [vupdraft](https://wordpress.org/support/users/vupdraft/) * (@vupdraft) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-errors-262/#post-15304083) * [@seath](https://wordpress.org/support/users/seath/) Can you see if you can use [https://wordpress.org/plugins/wp-crontrol/](https://wordpress.org/plugins/wp-crontrol/) to line up any cron jobs with the error’s appearance. Have you activated the alternate cron? * Thread Starter [Seath](https://wordpress.org/support/users/seath/) * (@seath) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-errors-262/#post-15304227) * [@vupdraft](https://wordpress.org/support/users/vupdraft/) I do not know what alternate cron is, so I ma guessing no. * I installed the plugin and this is what I get…. There’s a lot of stuff going on and I have no idea what …. * action_scheduler_run_queue [ “WP Cron” ] 2022-01-28 17:12:04 38 seconds ActionScheduler_QueueRunner- >run() Every minute * aiowps_hourly_cron_event None 2022-01-28 17:34:12 22 minutes 46 seconds AIOWPSecurity_Cronjob_Handler- >aiowps_hourly_cron_event_handler() Once Hourly * wp_privacy_delete_old_export_files None 2022-01-28 17:35:51 24 minutes 25 seconds wp_privacy_delete_old_export_files() Once Hourly * Elm_Plugin_emailErrors_hook None 2022-01-28 17:49:03 37 minutes 37 seconds Elm_Plugin- >emailErrors() 3600 seconds * Elm_Plugin_checkLogFileSize_hook None 2022-01-28 17:49:03 37 minutes 37 seconds Elm_Plugin->checkLogFileSize() 3600 seconds * wp_statistics_add_visit_hook None 2022-01-28 19:08:36 1 hour 57 minutes None Once Daily * fastvelocity_purge_old_cron_event None 2022-01-28 19:17:10 2 hours 5 minutes fvm_purge_old() Once Daily * wp_scheduled_auto_draft_delete None 2022-01-28 20:04:23 2 hours 52 minutes wp_delete_auto_drafts() Once Daily * wp_https_detection None 2022-01-28 20:07:37 2 hours 56 minutes wp_update_https_detection_errors() Twice Daily * wp_version_check None 2022-01-28 21:54:09 4 hours 42 minutes wp_version_check() Twice Daily * wp_update_plugins None 2022-01-29 00:18:05 7 hours 6 minutes wp_update_plugins() Twice Daily * wp_update_themes None 2022-01-29 00:18:05 7 hours 6 minutes wp_update_themes() Twice Daily * backwpup_update_message None 2022-01-29 00:34:13 7 hours 22 minutes None Twice Daily * backwpup_check_cleanup None 2022-01-29 00:34:13 7 hours 22 minutes None Twice Daily * backwpup_cron { “arg”: 2 } 2022-01-29 03:00:00 9 hours 48 minutes None Non-repeating * wp_statistics_dbmaint_hook None 2022-01-29 10:27:15 17 hours 15 minutes None Once Daily * wp_scheduled_delete None 2022-01-29 12:18:45 19 hours 7 minutes wp_scheduled_delete() Once Daily * delete_expired_transients None 2022-01-29 12:18:45 19 hours 7 minutes delete_expired_transients() Once Daily * aiowps_daily_cron_event None 2022-01-29 12:34:12 19 hours 22 minutes AIOWPSecurity_Cronjob_Handler- >aiowps_daily_cron_event_handler() Once Daily * sm_ping_daily None 2022-01-29 13:34:14 20 hours 22 minutes GoogleSitemapGeneratorLoader:: CallSendPingDaily() Once Daily * wp_statistics_geoip_hook None 2022-01-29 15:34:18 22 hours 22 minutes WP_STATISTICS\ Schedule->geoip_event() Once Daily * recovery_mode_clean_expired_keys None 2022-01-29 15:48:39 22 hours 37 minutes WP_Recovery_Mode->clean_expired_keys() Once Daily * flamingo_daily_cron_job None 2022-01-29 15:51:06 22 hours 39 minutes flamingo_schedule_function() Once Daily * backwpup_cron { “arg”: 1 } 2022-01-30 03:00:00 1 day 9 hours None Non-repeating * wp_statistics_referrerspam_hook None 2022-01-30 10:27:04 1 day 17 hours None Once Weekly * wp_site_health_scheduled_check None 2022-02-03 17:46:44 6 days WP_Site_Health- >wp_cron_scheduled_check() Once Weekly * wp_statistics_optimize_table None 2022-02-20 18:21:25 3 weeks 2 days None Once Every 4 Weeks` * Plugin Support [vupdraft](https://wordpress.org/support/users/vupdraft/) * (@vupdraft) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-errors-262/#post-15305841) * Hi, * You are looking for a hook that appears at the same time as the php error. I can’t see the time in the snippet you posted, do you see a hook t in the Cron Events that matches the time of the php error? Can you also go to your functions. php and take a screenshot of what is on line 6712? * Thread Starter [Seath](https://wordpress.org/support/users/seath/) * (@seath) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-errors-262/#post-15308641) * [@vupdraft](https://wordpress.org/support/users/vupdraft/) Hello, * UGH, so I was messing with that, trying to match the time of error with the cron job. And I discovered that every time any (including WP cron) runs it will generate the error. * As I told you before I do not have any custom function.php, the error points to the WP function.php in wp-included. Plus after updating to the WP 5.9 the error moved to line 6821 …. * `Warning: Cannot modify header information - headers already sent by (output started at /wp-cron.php:28) in /wp-includes/functions.php on line 6821` * and this is what’s on that line … * ``` function send_frame_options_header() { header( 'X-Frame-Options: SAMEORIGIN' ); } ``` * Plugin Contributor [Prashant Baldha](https://wordpress.org/support/users/pmbaldha/) * (@pmbaldha) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-errors-262/#post-15308847) * [@seath](https://wordpress.org/support/users/seath/) I have found that The send_frame_options_header() function is called in the init hook. It causes this error. This function should be called from the template_redirect action hook. This is causing this error. We will fix the issue in the next release. * Thanks for reporting the issue and giving us reason behind the issue. * Thread Starter [Seath](https://wordpress.org/support/users/seath/) * (@seath) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-errors-262/#post-15310707) * [@pmbaldha](https://wordpress.org/support/users/pmbaldha/) [@vupdraft](https://wordpress.org/support/users/vupdraft/) Thank you very much for taking the time to help me. I really appreciate it. * Plugin Contributor [Prashant Baldha](https://wordpress.org/support/users/pmbaldha/) * (@pmbaldha) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-errors-262/#post-15310774) * [@seath](https://wordpress.org/support/users/seath/) You’re welcome! * If you find All in One WP Security useful, then please give us a positive review, here: [https://wordpress.org/support/plugin/all-in-one-wp-security-and-firewall/reviews/#new-post](https://wordpress.org/support/plugin/all-in-one-wp-security-and-firewall/reviews/#new-post) * (If we’re not yet worth 5 stars, then please don’t review, but instead reply here to let us know why not – reviews less than 5 stars bring our average down!). * Best wishes, Prashant Viewing 10 replies - 1 through 10 (of 10 total) The topic ‘PHP errors’ is closed to new replies. * ![](https://ps.w.org/all-in-one-wp-security-and-firewall/assets/icon-256x256. png?rev=2798307) * [All-In-One Security (AIOS) – Security and Firewall](https://wordpress.org/plugins/all-in-one-wp-security-and-firewall/) * [Frequently Asked Questions](https://wordpress.org/plugins/all-in-one-wp-security-and-firewall/#faq) * [Support Threads](https://wordpress.org/support/plugin/all-in-one-wp-security-and-firewall/) * [Active Topics](https://wordpress.org/support/plugin/all-in-one-wp-security-and-firewall/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/all-in-one-wp-security-and-firewall/unresolved/) * [Reviews](https://wordpress.org/support/plugin/all-in-one-wp-security-and-firewall/reviews/) * 10 replies * 3 participants * Last reply from: [Prashant Baldha](https://wordpress.org/support/users/pmbaldha/) * Last activity: [4 years, 3 months ago](https://wordpress.org/support/topic/php-errors-262/#post-15310774) * Status: resolved