Title: PHP Warning: Cannot modify header information Last modified: October 29, 2024 --- # PHP Warning: Cannot modify header information * Resolved [dnsss](https://wordpress.org/support/users/dnsss/) * (@dnsss) * [1 year, 7 months ago](https://wordpress.org/support/topic/php-warning-cannot-modify-header-information-31/) * Hi! * I found the following warning in the PHP error log. * WP 6.6.2 PHP 8.2.20QSM 9.2.1 * ```wp-block-code PHP Warning: Cannot modify header information - headers already sent by (output started at /.../wp-content/plugins/quiz-master-next/php/classes/class-qmn-quiz-manager.php:443) in /.../wp-content/plugins/quiz-master-next/php/classes/class-qmn-quiz-manager.php on line 459, referer: https://.../wp-admin/admin.php?page=qsm_quiz_toolsPHP Warning: Cannot modify header information - headers already sent by (output started at /.../wp-content/plugins/quiz-master-next/php/classes/class-qmn-quiz-manager.php:443) in /.../wp-content/plugins/quiz-master-next/php/classes/class-qmn-quiz-manager.php on line 460, referer: https://.../wp-admin/admin.php?page=qsm_quiz_toolsPHP Warning: Cannot modify header information - headers already sent by (output started at /.../wp-content/plugins/quiz-master-next/php/classes/class-qmn-quiz-manager.php:443) in /.../wp-content/plugins/quiz-master-next/php/classes/class-qmn-quiz-manager.php on line 461, referer: https://.../wp-admin/admin.php?page=qsm_quiz_toolsPHP Warning: Undefined array key "contact_info_location" in /.../wp-content/plugins/quiz-master-next/php/classes/class-qsm-fields.php on line 97, referer: https://.../wp-admin/admin.php?page=mlw_quiz_options&quiz_id=1&tab=textPHP Warning: Undefined array key "loggedin_user_contact" in /.../wp-content/plugins/quiz-master-next/php/classes/class-qsm-fields.php on line 98, referer: https://.../wp-admin/admin.php?page=mlw_quiz_options&quiz_id=1&tab=textPHP Warning: Undefined array key "contact_disable_autofill" in /.../wp-content/plugins/quiz-master-next/php/classes/class-qsm-fields.php on line 99, referer: https://.../wp-admin/admin.php?page=mlw_quiz_options&quiz_id=1&tab=textPHP Warning: Undefined array key "disable_first_page" in /.../wp-content/plugins/quiz-master-next/php/classes/class-qsm-fields.php on line 100, referer: https://.../wp-admin/admin.php?page=mlw_quiz_options&quiz_id=1&tab=text ``` - This topic was modified 1 year, 7 months ago by [dnsss](https://wordpress.org/support/users/dnsss/). Viewing 9 replies - 1 through 9 (of 9 total) * [dhanush22](https://wordpress.org/support/users/dhanush22/) * (@dhanush22) * [1 year, 6 months ago](https://wordpress.org/support/topic/php-warning-cannot-modify-header-information-31/#post-18119508) * Hi **[@dnsss](https://wordpress.org/support/users/dnsss/)** , I hope this message finds you well, and please accept my apologies for the delayed response. * Thank you for sharing the detailed error logs. I have passed the information along with the issue to our development team, who are currently investigating it. I’ll follow up with a solution as soon as possible. * Thank you for your patience and cooperation. * Best regards, Dhanush * [dhanush22](https://wordpress.org/support/users/dhanush22/) * (@dhanush22) * [1 year, 6 months ago](https://wordpress.org/support/topic/php-warning-cannot-modify-header-information-31/#post-18127692) * Hi **[@dnsss](https://wordpress.org/support/users/dnsss/)** , I hope this message finds you well, and I apologize for the delay in my response. * Our development team is actively working on resolving the issue you’ve reported. To help us proceed efficiently, they have requested some specific information from your end, including: - The quiz URL - Server details - A list of active plugins * Providing these details will enable our team to replicate the issue accurately, allowing us to implement a timely fix. * Thank you for your cooperation. We look forward to hearing from you soon. * Best regards, * Thread Starter [dnsss](https://wordpress.org/support/users/dnsss/) * (@dnsss) * [1 year, 6 months ago](https://wordpress.org/support/topic/php-warning-cannot-modify-header-information-31/#post-18128184) * Hi. * Thank you for your response. * We are sorry, but for security reasons, we cannot provide the URL. - A list of active plugins * [https://wordpress.org/plugins/ad-inserter/](https://wordpress.org/plugins/ad-inserter/) * [https://wordpress.org/plugins/advanced-custom-fields/](https://wordpress.org/plugins/advanced-custom-fields/) * [https://wordpress.org/plugins/broken-link-checker/](https://wordpress.org/plugins/broken-link-checker/) * [https://wordpress.org/plugins/taxonomy-terms-order/](https://wordpress.org/plugins/taxonomy-terms-order/) * [https://wordpress.org/plugins/disable-author-archives/](https://wordpress.org/plugins/disable-author-archives/) * [https://wordpress.org/plugins/flexible-table-block/](https://wordpress.org/plugins/flexible-table-block/) * [https://wordpress.org/plugins/seo-automated-link-building/](https://wordpress.org/plugins/seo-automated-link-building/) * [https://wordpress.org/plugins/liquid-speech-balloon/](https://wordpress.org/plugins/liquid-speech-balloon/) * [https://wordpress.org/plugins/login-recaptcha/](https://wordpress.org/plugins/login-recaptcha/) * QSM – Export Results * Quiz And Survey Master * [https://wordpress.org/plugins/redirection/](https://wordpress.org/plugins/redirection/) * [https://wordpress.org/plugins/richtext-extension/](https://wordpress.org/plugins/richtext-extension/) * [https://oyakosodate.com/rinker/](https://oyakosodate.com/rinker/) * [https://wordpress.org/plugins/simple-custom-post-order/](https://wordpress.org/plugins/simple-custom-post-order/) * [https://wordpress.org/plugins/pubsubhubbub/](https://wordpress.org/plugins/pubsubhubbub/) * [https://wordpress.org/plugins/wp-mail-smtp/](https://wordpress.org/plugins/wp-mail-smtp/) * [https://wordpress.org/plugins/wp-multibyte-patch/](https://wordpress.org/plugins/wp-multibyte-patch/) * [https://wordpress.org/plugins/amazon-s3-and-cloudfront/](https://wordpress.org/plugins/amazon-s3-and-cloudfront/) * [https://wordpress.org/plugins/wp-super-cache/](https://wordpress.org/plugins/wp-super-cache/) * [https://wordpress.org/plugins/insert-headers-and-footers/](https://wordpress.org/plugins/insert-headers-and-footers/) * [https://wordpress.org/plugins/wps-hide-login/](https://wordpress.org/plugins/wps-hide-login/) * [https://wordpress.org/plugins/google-sitemap-generator/](https://wordpress.org/plugins/google-sitemap-generator/) * [dhanush22](https://wordpress.org/support/users/dhanush22/) * (@dhanush22) * [1 year, 6 months ago](https://wordpress.org/support/topic/php-warning-cannot-modify-header-information-31/#post-18135192) * Hi **[@dnsss](https://wordpress.org/support/users/dnsss/)** , I hope this message finds you well. Thank you for your prompt response and for providing information about the active plugins in use. * We understand that sharing the URL may be sensitive for security reasons. I’ll discuss this matter with our development team to see if we can replicate the issue without accessing the URL. If any additional steps or adjustments are needed on our end or if further information is required from you, I’ll be sure to keep you updated. * Thank you for your time and cooperation. * Best regards, Dhanush * [dhanush22](https://wordpress.org/support/users/dhanush22/) * (@dhanush22) * [1 year, 6 months ago](https://wordpress.org/support/topic/php-warning-cannot-modify-header-information-31/#post-18138106) * Hi **[@dnsss](https://wordpress.org/support/users/dnsss/)** , I hope this email finds you well. * We conducted thorough testing of QSM using the same plugins and add-ons provided from your end but were unable to replicate the warning you mentioned. Additionally, the debug log did not show any errors. * For your reference, here is a screencast demonstrating how we replicated the section on our end without encountering any PHP warnings: [View Screencast](https://www.awesomescreenshot.com/video/33641186?key=06750b35c932698406a9ac5f2eaf3471). * We completely understand if sharing the quiz URL feels uncomfortable due to security concerns. However, our priority is to resolve this issue for you as quickly as possible. If you prefer not to share the URL here, please feel free to reach out directly through the QSM support thread. * Thank you for your time and cooperation. We look forward to your thoughts and will assist you further as needed. * Best regards, Dhanush * Thread Starter [dnsss](https://wordpress.org/support/users/dnsss/) * (@dnsss) * [1 year, 6 months ago](https://wordpress.org/support/topic/php-warning-cannot-modify-header-information-31/#post-18140947) * Hi. * Thank you for debugging. * I also debugged again and found that the following error occurs when I run admin >QSM>Tools>Export. * This warning is probably occurring on the admin page. The referer also indicated the admin page. * ```wp-block-code PHP Warning: Cannot modify header information - headers already sent by (output started at /.../wp-content/plugins/quiz-master-next/php/classes/class-qmn-quiz-manager.php:443) in /.../wp-content/plugins/quiz-master-next/php/classes/class-qmn-quiz-manager.php on line 459, referer: https://.../wp-admin/admin.php?page=qsm_quiz_toolsPHP Warning: Cannot modify header information - headers already sent by (output started at /.../wp-content/plugins/quiz-master-next/php/classes/class-qmn-quiz-manager.php:443) in /.../wp-content/plugins/quiz-master-next/php/classes/class-qmn-quiz-manager.php on line 460, referer: https://.../wp-admin/admin.php?page=qsm_quiz_toolsPHP Warning: Cannot modify header information - headers already sent by (output started at /.../wp-content/plugins/quiz-master-next/php/classes/class-qmn-quiz-manager.php:443) in /.../wp-content/plugins/quiz-master-next/php/classes/class-qmn-quiz-manager.php on line 461, referer: https://.../wp-admin/admin.php?page=qsm_quiz_tools ``` - This reply was modified 1 year, 6 months ago by [dnsss](https://wordpress.org/support/users/dnsss/). * [dhanush22](https://wordpress.org/support/users/dhanush22/) * (@dhanush22) * [1 year, 6 months ago](https://wordpress.org/support/topic/php-warning-cannot-modify-header-information-31/#post-18144191) * Hi **[@dnsss](https://wordpress.org/support/users/dnsss/)** , I hope this email finds you well. * Thank you for sharing the detailed debugging steps. We have tested, replicated the warnings, and successfully resolved them. * Please find the updated function in the following Google Drive link: [Updated Function – Google Drive](https://docs.google.com/document/d/1nEBc-O2rF6ZqMF7-N--g5zFLdqUuU3au0p0VWJyRjP4/edit?usp=drive_link) * Replace the existing function in the file: **`PHP > classes > class-qsm-quiz- manager.php`** * **Important:** Ensure the function name matches before proceeding with the replacement. * We will also ensure this fix is included in the upcoming updates. If you have any questions or need further assistance, feel free to contact me. * Thank you for your cooperation and support. * Best regards, * [dhanush22](https://wordpress.org/support/users/dhanush22/) * (@dhanush22) * [1 year, 6 months ago](https://wordpress.org/support/topic/php-warning-cannot-modify-header-information-31/#post-18173572) * Hi **[@dnsss](https://wordpress.org/support/users/dnsss/)** , I hope this message finds you well. * As we have not received a response from you, we will proceed with marking this ticket as resolved. If you have any further questions or require additional assistance, please don’t hesitate to reach out. We will be happy to assist you. * Thank you for your time and attention. * Best regards, Dhanush * Thread Starter [dnsss](https://wordpress.org/support/users/dnsss/) * (@dnsss) * [1 year, 6 months ago](https://wordpress.org/support/topic/php-warning-cannot-modify-header-information-31/#post-18174672) * Hi [@dhanush22](https://wordpress.org/support/users/dhanush22/), * Thank you for your help. * I’m waiting for the new version to be released. * If the issue is resolved in the next version, you can close this issue. * Thank you. Viewing 9 replies - 1 through 9 (of 9 total) The topic ‘PHP Warning: Cannot modify header information’ is closed to new replies. * ![](https://ps.w.org/quiz-master-next/assets/icon-128x128.png?rev=3158087) * [Quiz and Survey Master (QSM) - Easy Quiz and Survey Maker](https://wordpress.org/plugins/quiz-master-next/) * [Frequently Asked Questions](https://wordpress.org/plugins/quiz-master-next/#faq) * [Support Threads](https://wordpress.org/support/plugin/quiz-master-next/) * [Active Topics](https://wordpress.org/support/plugin/quiz-master-next/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/quiz-master-next/unresolved/) * [Reviews](https://wordpress.org/support/plugin/quiz-master-next/reviews/) * 10 replies * 2 participants * Last reply from: [dnsss](https://wordpress.org/support/users/dnsss/) * Last activity: [1 year, 6 months ago](https://wordpress.org/support/topic/php-warning-cannot-modify-header-information-31/#post-18174672) * Status: resolved