{"id":19003704,"date":"2026-08-26T14:42:52","date_gmt":"2026-08-26T14:42:52","guid":{"rendered":"https:\/\/wordpress.org\/support\/topic\/plugin-causes-headers-already-sent-blocks-wp-login\/"},"modified":"2026-08-26T14:42:52","modified_gmt":"2026-08-26T14:42:52","slug":"plugin-causes-headers-already-sent-blocks-wp-login","status":"publish","type":"topic","link":"https:\/\/wordpress.org\/support\/topic\/plugin-causes-headers-already-sent-blocks-wp-login\/","title":{"rendered":"Plugin causes &#8220;headers already sent&#8221; \/ blocks WP login"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Hi,<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">After installing\/updating to version 5.0 (a month ago), this plugin&#8217;s main file began sending output from the very first line, which triggered repeated PHP &#8220;headers already sent&#8221; warnings.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In WordPress, this blocks login cookies and redirects \u2014 in our case it prevented access to <code>\/wp-admin<\/code> entirely. Our host&#8217;s support team traced the issue directly to this plugin and confirmed removing it restored normal login functionality.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Environment:<\/p>\n\n\n\n<ul>\n<li>Plugin version: 5.0<\/li>\n\n\n\n<li>WordPress: 7.1<\/li>\n\n\n\n<li>PHP: 7.4+ (per plugin requirements)<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Could you take a look at the plugin&#8217;s initialization code for any output (whitespace, echo, print, etc.) happening before headers are sent? Happy to provide further detail if useful.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Thanks<\/p>\n","protected":false},"template":"","class_list":["post-19003704","topic","type-topic","status-publish","hentry"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic\/19003704","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic"}],"about":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic\/19003704\/revisions"}],"wp:attachment":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/media?parent=19003704"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}