Cannot Connect To Internet

Hello friends. I have not been able to solve a computer’s internet problem for the last 2 days, that is, every time I try to connect the Internet to my computer, the DNS server not responding, issue is showing. I am currently using the internet from my mobile phone. This is why I’m having so much trouble using my computer. Guys, I don’t know why this is happening and how to fix this issue. Please help me to solve the problem. Any help will be appreciated.

Does this question involve Directory Opus in any way? I am not sure you have come to the correct forum for the question you're asking.