I recently noticed that Rank Math's sitemap.xml is no longer working on my site. After doing some digging and disabling code in my theme I noticed that whenever I removed the Metabox Relationships declarations the sitemap started working again. An example of the code I am commenting out can be found below:
thanks for looking into this. I found the issue. I had an extra newline before the first <?php which was causing this issue. I understand that this was not Meta Box related and apologies for wasting any of your time. Thanks and apologies once again.