To solve the issue of "DNS server isn't responding," you can manually enter the DBS address. Regarding this, you can try connecting through the preferred and alternative DNS addresses you entered yourself. So you can follow this process:
First of all, you will need to open the Command Prompt. To do so, you have to type the ipconfig /all. Data regarding network connections will be returned.
You have to open the network and Internet settings from the properties to have the correct DNS address.
Now open the TCP SETTING and the DNS address of the network operator.
Lastly, you have to apply the changes and connect the system to the network again.