This is similar to Unknown host error met for my Running App. Created and deployed new app:
fly services list
Services
PROTOCOL PORTS HANDLERS FORCE HTTPS PROCESS GROUP REGIONS MACHINES
TCP 8080 => 50051 [TLS] False app ams 2
fly status --all
App
Name = andig-1
Owner = personal
Hostname = andig-1.fly.dev
Image = andig-1:deployment-01HRPYWXJ711GYYG0F278FQ1E2
Machines
PROCESS ID VERSION REGION STATE ROLE CHECKS LAST UPDATED
app 2874310b651048 1 ams started 2024-03-11T14:33:48Z
app 6e82933c261528 1 ams started 2024-03-11T14:33:40Z
fly ips list
VERSION IP TYPE REGION CREATED AT
v6 2a09:8280:1::2d:9287:0 public (dedicated) global 3m49s ago
v4 66.241.124.217 public (shared) Jan 1 0001 00:00
Yet
nslookup andig-1.fly.dev
Server: 192.168.178.1
Address: 192.168.178.1#53
Non-authoritative answer:
*** Can't find andig-1.fly.dev: No answer
Btw, I had to manually allocate the IPs, the app had none (not even v6) after being created.