Hey there,
first of all I am a noob, just gotten into wordpress!
I use it to run my blog called 5monthsiniceland.com.
I wanted to do some search engine optimization. I submitted my sitemap.xml file generated by Yoast SEO to Google and Bing but now I think the file is broken. When clicking on it, I only get to a site with a little bit of text:
http://www.5monthsiniceland.com/sitemap_index.xml
I know it worked before. I installed the following plugins:
WP Performance Score Booster
WP Smush
WP Super Cache
After that it didn’t work any more.
I would appreciate any help. Please keep in mind, that I have almost no experience with wordpress, so please explain extensively 
Thanks to everybody in advance!
Best, Nils