Lost main brand keyword, looking for advice.

For my question im going to use the word "hotdog" to refer to my brand & domain. So my domain is hotdoginc.com & we've ranked #1 for "hotdog" for the past year+. This week I'm checking my keyword positions & visibility with SEMrush & I see our keyword "hotdog" has a loss. I check on Google & now there is a hotdog.com ranking #1 where I was. When I go to the site I get a page for Microsoft internet information services page & not their page. Does this mean that they are a new company that purchased hotdog.com & is creating their site? Any advice on how to get the branded keyword back? We still rank #1 for "hot dog" that's how we word our brand on the site.