"Unknown host" when I and my friend try to log in to our server

Hello,

A few days ago me and my friend created our server on Aternos, and it worked flawleslly

But somewhere around 20 Aug 23:00 UTC my friend had a problem with connecting to my server

it said "unknown host" or "timed out"

I can barely connect to my server

Am I doing something wrong? Or it affects other people?

Please help!

Edit: Server version: 1.16.2 Spigot (no plugins)

My friend can't connect at all, but I can sometimes join it when I restart the server

I tried that DynIP myself and it worked, but i don't know if my friend also has that issue.

I will ask it to connect to the DynIP instead as a temporary solution (it if will work)