Google cant fetch sub-sitemaps

I installed this plugin, it created a sitemap and sub-sitemaps.

After the sitemap was created i went straight to google search console and added the sitemap link.

However google couldn’t fetch the sub-sitemaps, it shows the status couldn’t fetch.

See this link to see how the image looks >> https://i.ibb.co/0JDjJzC/google-search-console-sitemaps.png