License Authentication Fails When Windows Cannot Connect to time.windows.com – Ranorex

If you see the following error message when your Windows system tries to synchronize time:

Can't connect to time.windows.com
"Connection to time.windows.com failed. Please check your network settings and ensure that access to time.windows.com is not blocked by your firewall or proxy."

This error indicates that your computer cannot connect to the Network Time Protocol (NTP) server time.windows.com to update its system clock. Maintaining accurate time is essential for many applications, including license authentication, as it helps prevent fraud and ensures the integrity of operations.

Allow NTP (Time Sync) Through the Firewall

Hint: NTP operates over UDP port 123.
Firewalls, by default, often block outbound connections on ports not commonly used by standard web browsers (like HTTP/HTTPS on TCP ports 80/443). If your firewall is blocking this port, your computer cannot send requests to time.windows.com or receive time synchronization responses.

To configure Windows Defender Firewall:

Press Win + R, type wf.msc, and press Enter.
On the left panel of the Windows Defender Firewall window, click Outbound Rules.
On the right side, click New Rule…
Select Port, and click Next.
Select UDP, in the Specific local ports field, type 123, and click Next.
Select Allow the connection, and click Next.
Apply the rule to Domain, Private, and Public profiles. Click Next.
Name the rule (e.g., Allow NTP (Port 123)) and click Finish.
Restart the Windows Time Service:
1. Open Command Prompt as administrator.
2. Type net stop w32time and press Enter.
3. Type net start w32time and press Enter.
4. You can try to force a synchronization: w32tm /resync

Once configured, your system should be able to connect to time.windows.com and synchronize time successfully.

Still seeing the error? Contact your IT department or network administrator to confirm that outbound UDP traffic on port 123 is not restricted by a company firewall or proxy.