{"id":18589308,"date":"2025-08-07T10:21:13","date_gmt":"2025-08-07T10:21:13","guid":{"rendered":"https:\/\/wordpress.org\/support\/topic\/invalid-function-name-error\/"},"modified":"2025-08-07T10:50:01","modified_gmt":"2025-08-07T10:50:01","slug":"invalid-function-name-error","status":"publish","type":"topic","link":"https:\/\/wordpress.org\/support\/topic\/invalid-function-name-error\/","title":{"rendered":"Invalid function name error"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Hi everyone,<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">I hope someone might be able to help me. I&#8217;m reviving an old blog of mine and installed a new theme, etc. as well as a handful of plugins I&#8217;ve used on numerous other websites without issue. This site of mine though has given me one issue after the other that I had to fix. The last one has left me scratching my head. At the bottom of every page I get this error code:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">call_user_func_array() expects parameter 1 to be a valid callback, function &#8216;wp_ob_end_flush_all&#8217; not found or invalid function name in&nbsp;<strong>\/home\/thenevzs\/public_html\/wp-includes\/class-wp-hook.php<\/strong>&nbsp;on line&nbsp;<strong>324<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Though I&#8217;ve been working WordPress sites for a few years I&#8217;ve not learned as much as I would hope. If someone could help me make sense of this issue and maybe tell me how to fix it I would be ever grateful. The website can be found here: <em>[ redundant link deleted ]<\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Thanks<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Stephan<\/p>\n","protected":false},"template":"","class_list":["post-18589308","topic","type-topic","status-publish","hentry","topic-tag-call_user_func_array"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic\/18589308","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":1,"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic\/18589308\/revisions"}],"predecessor-version":[{"id":18589355,"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic\/18589308\/revisions\/18589355"}],"wp:attachment":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/media?parent=18589308"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}