When you access your website from browser in your network then you need to it in
trusted site zone and additionally you need to turned ON anonymous access to get website access by any user in your LAN
to switch it ON see below snippet
Enable Anonymous access in IIS[
^]
Basically in your case, your application open some other application which needs authentication right ? so why don't you try with local Administrator user with Identity Impersonate tag
add below web.config
<system.web>
<authentication mode="Windows"></authentication>
<identity password="bar" username="foo" impersonate="true"></identity>
</system.web>