To fix a DNS leak, there are multiple ways to solve this.
- You can manually set a DNS server on your network adapter. (Ethernet or Wireless) You can follow this tutorial if you require help on this: https://188.8.131.52/#setup-instructions
- You can also set a DNS server on your router.
- Please make sure that you clear your DNS cache after doing any of the steps above. (Open CMD and type ipconfig /flushdns)