Open .htaccess file of your phpBB root folder, search for this line: RewriteRule ^(.*)$ app.php [QSA,L] just below add the follow: #p reserved in WP RewriteCond %{QUERY_STRING} ^(.*)(iframe=true&)(.*)(p=)([0-9]+)(.*)?$ RewriteRule . /yourwp/index.php/forum/?%3post_id=%5%6 [R,L] #all others RewriteCond %{QUERY_STRING} ^(.*)(iframe=true)(.*)$ RewriteRule . /yourwp/index.php/forum/?%3 [R,L] Change on lines RewriteRule . /yourwp/index.php/forum/?%3post_id=%5%6 [R,L] and RewriteRule . /yourwp/index.php/forum/?%3 [R,L] the relative…