Can't join my server. Unknown Host or Can't Resolve Hostname.

I am not able to join my server. The error I'm getting is often either Can't resolve hostname or Unknown host. This has been going on for like past 3 hours now. I've tried several things from forums but nothing seems to work. Me and my friend both are unable to join.

I changed my Ipv4 and Ipv6 DNS but didn't work. It still shows the same error.

Edit: Should I try my PC after following the guide?

Sure. Wait a second.

Screenshot of the error or the DNS?

Yeah ok

Sure wait a second.

Thank you so much. After connecting to my dynip it worked perfectly!