See above image and same error with you. So remove last added [?>] from functions.php file or include files of functions.php. Then Save and retry to see wp-sitemap.xml.
Hope This page contains the following error problem solve. If this solution not working on your website so contact-us. We will try to solve your sitemap’s problem.
What is This
This page contains the following error is error type message, When any missing or conflict code use on default wp-sitemap’s filter.
