wp_mail strips out the link url from the anchor tag in mail content
You are missing a single quote ‘ $activation_url=”mobileappname://accesstoken#w34rdgtsrt5v6m; should be… $activation_url = “mobileappname://accesstoken#w34rdgtsrt5v6m’; or (using double quotes)… $activation_url = “mobileappname://accesstoken#w34rdgtsrt5v6m”; Update: See this codex entry for more: http://codex.wordpress.org/Function_Reference/wp_mail add_filter( ‘wp_mail_content_type’, ‘set_html_content_type’ ); wp_mail( ‘[email protected]’, ‘The subject’, ‘<p>The <em>HTML</em> message</p>’ ); remove_filter( ‘wp_mail_content_type’, ‘set_html_content_type’ ); // reset content-type to to avoid conflicts — http://core.trac.wordpress.org/ticket/23578 function set_html_content_type() … Read more