Firewall blocks, outdated cached DNS data, and software incompatibility are all potential causes of Windows 11's VPN not working issues
Flush the DNS
Click the magnifying glass icon on the taskbar.
To find the Command Prompt, enter the cmd keyword in the search box.
Next, click the Command Prompt’s Run as administrator option
Input these separate commands by pressing Enter after each:
ipconfig /release
ipconfig /flushdns
ipconfig /renew
netsh int ip reset
netsh winsock reset
Close the Command Prompt.
Select Power, then Restart Start menu options.
And see if it helps,
Thank you
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