Yoast sitemap hick ups

HI there,

The Yoast site map works and many times not!! My site: https://www.anettemossbacher.com

I use the Yoast SEO plugin, so far so good, but the sitemap is sometimes accessible for web tools and many times not, than I get the message: Temporarily unreachable

I notice the “disappearance” usually when the Google refer links get less and less, till none shows up in analytics. Well, I had it 2x now so I switched back to the Google XML Plugin, this one stays at least alive all time. I went than 2x back to Yoast sitemap, it was finally “alive” and available again. For me it looks like a hick ups, “alive” or “disappeared”. Disappearance happens in silence, of course ??

I love the Yoast SEO plugin and the sitemap. The configuration is easy to use and easy to understand. I would love to have the Yoast sitemap …sitemap_index.xml all times visible / alive.
How can I achieve this? Is there any tiny code I need to insert or do I need to feed it with vitamins ? ??

Cheers Anette

PS I did updated the plugin to the latest version. That the sitemap got seen by webmaster tools, I had to switch Yoast off and on again as well clear the cache.