The PHP preg_replace() function failed to remove the WPSSO Core meta tag section — this could be an indication of a problem with PHP’s PCRE library or a webpage filter corrupting the WPSSO Core meta tags.
This is not a bug – it’s a warning that WPSSO detected an issue on the server.
Since the webpage HTML markup looked correct, we suggested the customer enable the PHP and WordPress error log using the WP_DEBUG constant, and activate the Query Monitor plugin – and we provided a link to this documentation for information on how to do that:
The customer reported that he did this, but did not report any errors from PHP or WordPress, so we suggested he update his version of PHP, or ask his hosting provider to update his PHP package to fix any known PHP PCRE bugs.
At this point, the customer left the review above. I’m not sure why – the customer stopped responding to any of our questions – as best I can tell, he expected us to update the PHP package on his server for him, which is not something we can technically do – only a site owner or hosting provider can update an application package on a server.