The browsers that the app are searching on my laptop are Chrome, Firefox and chrome. It doesn't seem to be seeing Safari. Is there something I can do to fix that?
There are other ways to identify your browser but almost certainly this app is using the user agent header and perhaps your browser (or an extension/add-on to it) is obfuscating this.
You can test your browser against EFF's Panopticlick. The site has quite a lot of information on browser identification: