XML Sitemap errors

XML Sitemap is not being generated correctly. Our website domain (filmreviewonline.com) in some parts is being replaced with other domains. This has happened in both the list of the XML Sitemap Index file which contains 51 sitemaps and the actual sitemaps themselves. If it gets it wrong it is wrong throughout one of the sitemap list.

Turning off the sitemap function or re-saving the permalinks regenerates them and mostly corrected the sitemaps but not entirely.

Any ideas?

Examples
https://dc-93699087.filmreviewonline.com/tag/matt-alvarez/
should be…
https://filmreviewonline.com/tag/matt-alvarez/

other examples are…
http://gresents.com/2010/06/03/universal-studios-backlot-reconstruction-details/
https://mail.inwonderland.co/2009/05/26/drag-me-to-hell-sam-raimi/
These domains are not mine! Hack??

Note: Switched to https after seemly having corrected the error but new sitemaps still have errors. (Additional note, using PHP7).

https://wordpress.org/plugins/wordpress-seo/