Title: Topic Tag: Cannot modify header information | WordPress.org --- # Topic Tag: Cannot modify header information 1 [2](https://wordpress.org/support/topic-tag/cannot-modify-header-information/page/2/?output_format=md) [3](https://wordpress.org/support/topic-tag/cannot-modify-header-information/page/3/?output_format=md)… [5](https://wordpress.org/support/topic-tag/cannot-modify-header-information/page/5/?output_format=md) [6](https://wordpress.org/support/topic-tag/cannot-modify-header-information/page/6/?output_format=md) [7](https://wordpress.org/support/topic-tag/cannot-modify-header-information/page/7/?output_format=md) [→](https://wordpress.org/support/topic-tag/cannot-modify-header-information/page/2/?output_format=md) - Topic - Participants - Replies - Last Post * - [[Speed Optimizer - The All-In-One Performance-Boosting Plugin] PHP error: Cannot modify header information](https://wordpress.org/support/topic/php-error-cannot-modify-header-information-2/) - Started by: [Dominique DC](https://wordpress.org/support/users/dominique_delcourt_com/) - 3 - 3 - [1 year, 3 months ago](https://wordpress.org/support/topic/php-error-cannot-modify-header-information-2/#post-18262223) - [Vladimir Trandev](https://wordpress.org/support/users/vtrandev/) * - [[Wordfence Security - Firewall, Malware Scan, and Login Security] Cannot modify header!](https://wordpress.org/support/topic/cannot-modify-header-15/) - Started by: [tonygao](https://wordpress.org/support/users/tonygao/) - 3 - 2 - [2 years ago](https://wordpress.org/support/topic/cannot-modify-header-15/#post-17736101) - [wfmargaret](https://wordpress.org/support/users/wfmargaret/) * - [[Custom Fonts - Host Your Fonts Locally] Getting “Warning: Cannot modify header” when using Custom Fonts](https://wordpress.org/support/topic/getting-warning-cannot-modify-header-when-using-custom-fonts/) - Started by: [Anthyx](https://wordpress.org/support/users/anthyx/) - 3 - 4 - [2 years, 5 months ago](https://wordpress.org/support/topic/getting-warning-cannot-modify-header-when-using-custom-fonts/#post-17276406) - [Herman Asrori (BSF)](https://wordpress.org/support/users/bsfherman/) * - [[Custom Fonts - Host Your Fonts Locally] Cannot Modify Header Information…](https://wordpress.org/support/topic/cannot-modify-header-information-190/) - Started by: [juleshenson](https://wordpress.org/support/users/juleshenson/) - 7 - 2 - [2 years, 8 months ago](https://wordpress.org/support/topic/cannot-modify-header-information-190/#post-17027778) - [juleshenson](https://wordpress.org/support/users/juleshenson/) * - [[Yoco Payments] Warning: Cannot modify header information](https://wordpress.org/support/topic/warning-cannot-modify-header-information-222/) - Started by: [bromponie99](https://wordpress.org/support/users/bromponie99/) - 1 - 1 - [2 years, 8 months ago](https://wordpress.org/support/topic/warning-cannot-modify-header-information-222/#post-16989044) - [bromponie99](https://wordpress.org/support/users/bromponie99/) * - [[Spam protection, Honeypot, Anti-Spam by CleanTalk] Undefined Index / Cannot Modify Header Info error](https://wordpress.org/support/topic/undefined-index-cannot-modify-header-info-error/) - Started by: [jshields](https://wordpress.org/support/users/jshields/) - 2 - 3 - [3 years, 5 months ago](https://wordpress.org/support/topic/undefined-index-cannot-modify-header-info-error/#post-16267386) - [sergecleantalk](https://wordpress.org/support/users/sergecleantalk/) * - [[Simple Discount Rules for Woocommerce] Php Warning Cannot modify header information – headers already sent by](https://wordpress.org/support/topic/php-warning-cannot-modify-header-information-headers-already-sent-by-2/) - Started by: [reeper6868](https://wordpress.org/support/users/reeper6868/) - 3 - 5 - [3 years, 7 months ago](https://wordpress.org/support/topic/php-warning-cannot-modify-header-information-headers-already-sent-by-2/#post-16096621) - [Leandro](https://wordpress.org/support/users/leandroprz/) * - [[WooCommerce] WooCommerce Causing Fatal Error On Activation](https://wordpress.org/support/topic/woocommerce-causing-fatal-error-on-activation-2/) - Started by: [Tony S.](https://wordpress.org/support/users/tony-s/) - 7 - 6 - [3 years, 12 months ago](https://wordpress.org/support/topic/woocommerce-causing-fatal-error-on-activation-2/#post-15644096) - [nathvi V. a11n](https://wordpress.org/support/users/nathvi/) * - [[MP3 Audio Player – Music Player, Podcast Player & Radio by Sonaar] Cannot modify header information](https://wordpress.org/support/topic/cannot-modify-header-information-174/) - Started by: [hinemann](https://wordpress.org/support/users/hinemann/) - 2 - 2 - [4 years, 6 months ago](https://wordpress.org/support/topic/cannot-modify-header-information-174/#post-15054019) - [hinemann](https://wordpress.org/support/users/hinemann/) * - [[Hummingbird Performance - Cache & Page Speed Optimization for Core Web Vitals | Critical CSS | Minify CSS | Defer CSS Javascript | CDN] `Warning: Cannot modify header information](https://wordpress.org/support/topic/warning-cannot-modify-header-information-210/) - Started by: [indusvalleytech](https://wordpress.org/support/users/indusvalleytech/) - 3 - 2 - [4 years, 11 months ago](https://wordpress.org/support/topic/warning-cannot-modify-header-information-210/#post-14499617) - [Patrick – WPMU DEV Support](https://wordpress.org/support/users/wpmudevsupport12/) * - [[Stock Manager for WooCommerce] error: “cannot modify header…” since update](https://wordpress.org/support/topic/error-cannot-modify-header-since-update/) - Started by: [horiamar](https://wordpress.org/support/users/horiamar/) - 4 - 9 - [4 years, 11 months ago](https://wordpress.org/support/topic/error-cannot-modify-header-since-update/#post-14501144) - [storeapps](https://wordpress.org/support/users/storeapps/) * - [[Psychological tests & quizzes] Array and string offset access syntax with curly braces is deprecated](https://wordpress.org/support/topic/array-and-string-offset-access-syntax-with-curly-braces-is-deprecated-9/) - Started by: [Ram Freedman](https://wordpress.org/support/users/ramf/) - 2 - 3 - [5 years, 1 month ago](https://wordpress.org/support/topic/array-and-string-offset-access-syntax-with-curly-braces-is-deprecated-9/#post-14222902) - [ustimenko](https://wordpress.org/support/users/ustimenko/) * - [Creating default object from empty value in – cannot post](https://wordpress.org/support/topic/creating-default-object-from-empty-value-in-cannot-post/) - Started by: [sweetiowa](https://wordpress.org/support/users/sweetiowa/) - 3 - 6 - [5 years, 2 months ago](https://wordpress.org/support/topic/creating-default-object-from-empty-value-in-cannot-post/#post-14104325) - [rameshmehay](https://wordpress.org/support/users/rameshmehay/) * - [[User Switching] Plugin Conflict with Easy Testimonials: Invalid header error](https://wordpress.org/support/topic/plugin-conflict-with-easy-testimonials-invalid-header-error/) - Started by: [Debra Lloyd](https://wordpress.org/support/users/deb-lloyd/) - 2 - 2 - [5 years, 3 months ago](https://wordpress.org/support/topic/plugin-conflict-with-easy-testimonials-invalid-header-error/#post-13967339) - [Debra Lloyd](https://wordpress.org/support/users/deb-lloyd/) * - [[WooCommerce] Lots of warnings – woocommerce plugins error](https://wordpress.org/support/topic/warning-continue-targeting-equivalent-to-break/) - Started by: [ejmart](https://wordpress.org/support/users/ejmart/) - 2 - 2 - [5 years, 7 months ago](https://wordpress.org/support/topic/warning-continue-targeting-equivalent-to-break/#post-13411705) - [ejmart](https://wordpress.org/support/users/ejmart/) * - [[Qualpay Payment Plugin for WooCommerce] Cannot Modify Header Information](https://wordpress.org/support/topic/cannot-modify-header-information-163/) - Started by: [julierachlin1](https://wordpress.org/support/users/julierachlin1/) - 1 - 0 - [5 years, 11 months ago](https://wordpress.org/support/topic/cannot-modify-header-information-163/) - [julierachlin1](https://wordpress.org/support/users/julierachlin1/) * - [[Under Construction] Warning: Cannot modify header information – headers already sent by class-wp-que](https://wordpress.org/support/topic/warning-cannot-modify-header-information-headers-already-sent-by-class-wp-que/) - Started by: [steindialog](https://wordpress.org/support/users/steindialog/) - 2 - 6 - [5 years, 11 months ago](https://wordpress.org/support/topic/warning-cannot-modify-header-information-headers-already-sent-by-class-wp-que/#post-12863833) - [Manuel Rocha](https://wordpress.org/support/users/manuelrocha88/) * - [Cannot modify header information](https://wordpress.org/support/topic/cannot-modify-header-information-162/) - Started by: [sundaymasterclass](https://wordpress.org/support/users/sundaymasterclass/) - 2 - 1 - [6 years ago](https://wordpress.org/support/topic/cannot-modify-header-information-162/#post-12704762) - [James Huff](https://wordpress.org/support/users/macmanx/) * - [Bug in my admin page?](https://wordpress.org/support/topic/bug-in-my-admin-page/) - Started by: [delfijurado](https://wordpress.org/support/users/delfijurado/) - 3 - 2 - [6 years ago](https://wordpress.org/support/topic/bug-in-my-admin-page/#post-12668189) - [Nigel M Rodgers](https://wordpress.org/support/users/rodgersnigel/) * - [[Meta pixel for WordPress] Error with Facebook Pixel and WP Forms](https://wordpress.org/support/topic/error-with-facebook-pixel-and-wp-forms/) - Started by: [jonasst](https://wordpress.org/support/users/jonasst/) - 2 - 4 - [6 years ago](https://wordpress.org/support/topic/error-with-facebook-pixel-and-wp-forms/#post-12726190) - [Facebook](https://wordpress.org/support/users/facebook/) * - [[Visual Form Builder] VFB PRo shows error after submit Cannot modify header information](https://wordpress.org/support/topic/vfb-pro-shows-error-after-submit-cannot-modify-header-information/) - Started by: [riya0011](https://wordpress.org/support/users/riya0011/) - 1 - 1 - [6 years, 3 months ago](https://wordpress.org/support/topic/vfb-pro-shows-error-after-submit-cannot-modify-header-information/#post-12345831) - [Jan Dembowski](https://wordpress.org/support/users/jdembowski/) * - [[Sticky Add to Cart for WooCommerce] Cannot modify header information](https://wordpress.org/support/topic/cannot-modify-header-information-156/) - Started by: [web88](https://wordpress.org/support/users/web88/) - 5 - 5 - [5 years, 10 months ago](https://wordpress.org/support/topic/cannot-modify-header-information-156/#post-13112129) - [arturdlugosz](https://wordpress.org/support/users/arturdlugosz/) * - [[Infinite-Scroll] Notice: Undefined index: a:1:{s:3:”ssl”;b:1;} in \wp-includes\class-requests](https://wordpress.org/support/topic/notice-undefined-index-a1s3sslb1-in-wp-includesclass-requests/) - Started by: [i_Mike](https://wordpress.org/support/users/i_mike/) - 2 - 1 - [6 years, 1 month ago](https://wordpress.org/support/topic/notice-undefined-index-a1s3sslb1-in-wp-includesclass-requests/#post-12551805) - [armagedescu](https://wordpress.org/support/users/armagedescu/) * - [[WP Cerber Security, Anti-spam & Malware Scan] headers already sent](https://wordpress.org/support/topic/headers-already-sent-40/) - Started by: [glouton](https://wordpress.org/support/users/glouton/) - 2 - 11 - [6 years, 5 months ago](https://wordpress.org/support/topic/headers-already-sent-40/#post-12214752) - [gioni](https://wordpress.org/support/users/gioni/) * - [[Postmatic Social Commenting] php warning Head](https://wordpress.org/support/topic/php-warning-head/) - Started by: [hbrandes](https://wordpress.org/support/users/hbrandes/) - 1 - 0 - [6 years, 6 months ago](https://wordpress.org/support/topic/php-warning-head/) - [hbrandes](https://wordpress.org/support/users/hbrandes/) * - [[Featured Images in RSS for Mailchimp & More] Php error when the cache is cleared](https://wordpress.org/support/topic/php-error-when-the-cache-is-cleared/) - Started by: [soydanielromero](https://wordpress.org/support/users/soydanielromero/) - 2 - 1 - [6 years, 6 months ago](https://wordpress.org/support/topic/php-error-when-the-cache-is-cleared/#post-12085309) - [Rob @ 5 Star Plugins](https://wordpress.org/support/users/5starplugins/) * - [[Yoast SEO - Advanced SEO with real-time guidance and built-in AI] Cannot modify header information – headers already](https://wordpress.org/support/topic/cannot-modify-header-information-headers-already-2/) - Started by: [Ambyomoron](https://wordpress.org/support/users/josiah-s-carberry/) - 2 - 1 - [6 years, 11 months ago](https://wordpress.org/support/topic/cannot-modify-header-information-headers-already-2/#post-11580485) - [Pcosta88](https://wordpress.org/support/users/pcosta88/) * - [New Issue, Cannot Modify Header Information Warning](https://wordpress.org/support/topic/new-issue-cannot-modify-header-information-warning/) - Started by: Anonymous User 853254 - 2 - 4 - [7 years, 4 months ago](https://wordpress.org/support/topic/new-issue-cannot-modify-header-information-warning/#post-11018943) - Anonymous User 853254 * - [[Featured Images in RSS for Mailchimp & More] Clashes with WP Rocket Plugin](https://wordpress.org/support/topic/clashes-with-wp-rocket-plugin/) - Started by: [emilyluxton](https://wordpress.org/support/users/emilyluxton/) - 3 - 5 - [7 years, 5 months ago](https://wordpress.org/support/topic/clashes-with-wp-rocket-plugin/#post-10955389) - [crzyhrse](https://wordpress.org/support/users/crzyhrse/) * - [[Mastodon Auto Share] 3 warnings after publish (mime_content_type & Cannot modify header information)](https://wordpress.org/support/topic/3-warnings-after-publish-mime_content_type-cannot-modify-header-information/) - Started by: [krnd](https://wordpress.org/support/users/krnd/) - 1 - 0 - [7 years, 8 months ago](https://wordpress.org/support/topic/3-warnings-after-publish-mime_content_type-cannot-modify-header-information/) - [krnd](https://wordpress.org/support/users/krnd/) *   1 [2](https://wordpress.org/support/topic-tag/cannot-modify-header-information/page/2/?output_format=md) [3](https://wordpress.org/support/topic-tag/cannot-modify-header-information/page/3/?output_format=md)… [5](https://wordpress.org/support/topic-tag/cannot-modify-header-information/page/5/?output_format=md) [6](https://wordpress.org/support/topic-tag/cannot-modify-header-information/page/6/?output_format=md) [7](https://wordpress.org/support/topic-tag/cannot-modify-header-information/page/7/?output_format=md) [→](https://wordpress.org/support/topic-tag/cannot-modify-header-information/page/2/?output_format=md) ## Topics ### Topics with no replies ### Non-support topics ### Resolved topics ### Unresolved topics ### All topics ## Feeds * [RSS Recent Posts](https://wordpress.org/support/forums/feed/) * [RSS Recent Topics](https://wordpress.org/support/topics/feed/)