Letsencrypt DNS problem looking up A
I successfully installed an SSL certificate for one of my domains the other day using your tutorial. Today I tried to general an SSL certificate for a second domain, and I'm getting the error "DNS problem: NXDOMAIN looking up A for [the domain]". Now the detail says to make sure the DNS A record contains the right IP address. I checked, it does.
Next it suggests to make sure no firewalls are preventing the server from communicating. How could that be a problem when I've done this before with no problem? I have not installed any firewalls or anything else for that matter since then.
Could this DNS problem have anything to do with the massive DDoS attack that's occurring today? Suggestions appreciated.