Many users of the Cisco AnyConnect Secure Mobility Client had this issue. If you get the message “VPN failed due to unsuccessful domain name resolution,” it means your Cisco customers aren’t able to establish a secure VPN connection. There’s a problem with your DNS settings as well.
It is usually addressed with simple DNS tinkering and the Cisco AnyConnect Client is used to establish a VPN connection. Verify that AnyConnect is correctly installed and ready to use on your computer from the client-side. This ensures that the AnyConnect Client isn’t the source of the problem.
What are the best ways to fix a VPN connection that has failed due to a DNS error?
Let’s have a look at the methods given below.
Method 1: Modify DNS Configuration
- Right-click the start menu in Windows 10 and select Network Connections.
- Now that you can see the network to which you’re connected, right-click it and select Properties.
- Select Internet Protocol Version 4 (TCP/IPv4) and double-click it.
- A new dialogue box will appear, and you must select automatically obtain DNS server address.
- To save your settings, click Ok.
Third-party VPN clients, such as Cisco VPN, do not allow static IP connections, which is one of the leading causes of VPN connection failure errors. If you’re using Google Public DNS, Open DNS, or another similar service, you’ll need to switch to a dynamic configuration.
Method 2: Repair the file anyconnect.xml
The best way to fix the anyconnect.xml file is to uninstall the Cisco AnyConnect Client and reset your computer. Then, one by one, install a fresh copy of the software. Finally, double-check that it’s installed correctly.
Because the main cause of the “VPN connection failed due to unsuccessful domain name resolution” error is that the anyconnect.xml file can become corrupted, preventing a VPN connection from being established. You could also try connecting to a different region. Perhaps it will be able to establish a successful connection and repair the file.
Method 3: Reinstalling Your Operating System
Finally, if all of the previous procedures fail to resolve the issue, the ultimate option is to install a fresh copy of the operating system. The Cisco client can then be installed when it has resolved all of your unique DNS settings. Take a backup of all of your crucial data and folders before reinstalling Windows OS.
After that, you can either reset your computer or install a fresh copy of Windows. You can receive all of the options by default by doing so. After that, all you have to do is properly install the Cisco client and test it to see if it can establish a VPN connection.
Our article is about fixing one of the errors (VPN failed because of unsuccessful domain name resolution). You can apply the procedure to get rid of this error. Dont forget to send us your suggestions and feedback. Goodbye!