Sitemaps Error Google on Search Console

Hi, first of all, thank you very much for this awesome SEO plugin.

Now let’s come to my problem;

I am using RankMath on my multiple websites but one of my websites is getting sitemap error on Google Search Console.

It’s a year old website, was working fine but suddenly I noticed that all my pages were disappeared from Google SERPs, and then I checked my GSC, and I got to know that my sitemaps are showing error as well a showing “Zero Discovered URLs”.

Find here: https://snipboard.io/CxkIQo.jpg

I have deleted the sitemaps and resubmitted as well as reindex my pages individually.

At this moment my rankings are dropped from page one to page two as they were disappeared from sitemaps from long I assume, but the sitemaps issue is still there.

Kindly help me fix this issue as it is very crucial hope you understand.

Thanks.
Wasim