need xml sitemap making software

I need one good xml sitemap making wordpress plugin . I’m currently using google xml sitemap and having problem . When i submitted the website’s sitemap i got this error in Google Webmaster’s tools panel

Network unreachable: DNS issue
We encountered an error while trying to access your Sitemap. Please ensure your Sitemap follows our guidelines and can be accessed at the location you provided and then resubmit.

my sitemap location :: https://nepallica.com/sitemap.xml/