White page for Sitemap

I have 2 sites on subdomains and I get a white screen for each of the site maps ??

https://steamshowerstore.co.uk/blog/sitemap_index.xml
https://poshh.co.uk/living/sitemap_index.xml

Here is what my server people say – can anyone help me please

Do you believe that the poshh conf should contain some of the config here that the others do? This is all sitemap related config in Nginx:
[root@194 ~]# grep sitemap /etc/nginx/conf.d/*
grep: /etc/nginx/conf.d/backup: Is a directory
/etc/nginx/conf.d/fitnessauthority.co.uk.conf: rewrite /sitemap_index.xml$ /index.php?sitemap=1 last;
/etc/nginx/conf.d/fitnessauthority.co.uk.conf: rewrite /([^/]+?)-sitemap([0-9]+)?.xml$ /index.php?sitemap=$1&sitemap_n=$2 last;
/etc/nginx/conf.d/poshh.co.uk.conf: rewrite (.*)/sitemap_index.xml$ /index.php?sitemap=1 permanent;
/etc/nginx/conf.d/steamshowerstore.co.uk.conf:rewrite ^/blog/sitemap_index.xml$ /sssblog//index.php?sitemap=1 last;
/etc/nginx/conf.d/steamshowerstore.co.uk.conf:rewrite /sssblog/([^/]+?)-sitemap([0-9]+)?.xml$ /sssblog//index.php?sitemap=$1&sitemap_n=$2 last;`