Are you wanting to access your sites remotely or only via the local LAN?
If you’re aiming for remote access then you can’t use the 192.168.* range as that’s the up address behind your NAT/router. You have use your public IP and do port forwarding from your router.
some query community:!ultralight.world would search your community. Now, if this community is less than 24hrs old, it may not have been indexed yet, so you may just need to wait a day or so.
I just tested with https://www.search-lemmy.com/results?query=test+community%3A!ultralight%40lemmy.world&page=1 I was able to at least find 2 posts.
Are you able to query to see what IP address that domain returns? Does it return the 192.168.x address that you set?
Edit: But the idea is to first see where the connection is failing… first see what error your browser is returning? 5xx? 4xx? This can be an indication as to where the error is happening. But high-level check DNS first, see if
nslookupordigreturn the IP address that you set. (Remember changes to DNS entries can take time to propagate). Assuming all of that is correct, then check to see what nginx is showing in its logs. Do you see it logging anything every time you try and access it via the domain name? Next up is checking the logs from plex itself, does it show any logs coming though? etc… But the idea is to find where the connection is breaking down.