The problem:
Err:1 http://us.archive.ubuntu.com/ubuntu cosmic InRelease
Could not resolve ‘us.archive.ubuntu.com’
Solution:
/etc sudo nano resolv.conf
nameserver 8.8.8.8
nameserver 8.8.4.4
nameserver 2001:4860:4860::8888
nameserver 2001:4860:4860::8844
Woala! The server is again online!