Your network contains an Active Directory Domain Services (AD DS) domain named contoso.

net use m: \\contoso.com\files\folder1

A domain-based DFS Namespace is accessed using the domain name as the server component of the UNC path, in the form \\ < domain > \ < namespace > \ < folder > , precisely so that clients are insulated from which physical server is actually hosting the namespace or the underlying share; this is the defining benefit of a domain-based namespace over a direct UNC path. Because the requirement explicitly says the solution must use the path of the DFS Namespace, rather than a direct reference to the file server, the command must use \\contoso.com (the domain name) rather than \\Server1.contoso.com or \\Server2.contoso.com, both of which are specific server names and would bypass the namespace referral entirely. The namespace itself is named Files, and the folder created inside it is Folder1, so the path beneath the domain name must be \files\folder1, not \files\share1\folder1 (which incorrectly includes the underlying share name that DFS abstracts away) and not a bare \folder1 (which omits the namespace name and would not resolve). The complete command is therefore net use m: \\contoso.com\files\folder1, which the DFS Referral service transparently resolves to \\Server2.contoso.com\Share1\Folder1 behind the scenes.