An organization has deployed DirectAccess as an optional Virtual Private Network $($VPN$)$ solution for its remote users. There is also an existing IPsec VPN already in place. The users' computers are a mix of various versions of Windows $10.$ Certain users can connect properly using DirectAccess and others are not able to at all. The original IPsec VPN solution continues to work for all users. Which of the following are potential reasons for these access issues?