在宝塔网站NGINX配置中，在server{}中添加以下代码，即可解决问题
#Yoast SEO Sitemaps
location ~ ([^/]*)sitemap(.*).x(m|s)l$ {
## this rewrites sitemap.xml to /sitemap_index.xml
rewrite ^/sitemap.xml$ /sitemap_index.xml permanent;
## this makes the XML sitemaps work
rewrite ^/([a-z]+)?-?sitemap.xsl$ /index.php?yoast-sitemap-xsl=$1 last;
rewrite ^/sitemap_index.xml$ /index.php?sitemap=1 last;
rewrite ^/([^/]+?)-sitemap([0-9]+)?.xml$ /index.php?sitemap=$1&sitemap_n=$2 last;
}