Final answer:
The most likely reason for the connection issue is the firewall not allowing the connection through port 3389. Check your firewall settings to resolve the problem.
Step-by-step explanation:
The MOST likely reason that you cannot connect to the employee's desktop is that your firewall is not set up to allow the connection through port 3389. Remote Desktop Protocol (RDP) uses port 3389 for communication between the remote desktop and the local computer. If your firewall is blocking this port, you won't be able to establish a connection.
Other possible reasons for the connection issue include the remote session from the Level 1 operator not being disconnected or having the wrong IP address for the employee's computer. However, based on the given options, the firewall configuration is the most likely culprit.
To resolve the issue, you'll need to check your firewall settings and ensure that port 3389 is allowed for Remote Desktop traffic. You may need to consult your IT department or network administrator for assistance with modifying the firewall.