I was getting a timeout, then and now. A 'no route to host' would be kinda weird, as in, usually this means something responds with an ICMP packet? Did you get this error all the time?
Yes, for port 80 to this domain I have only ever seen "No Route to Host". I can reach port 22 and for 8001 I have always gotten "Connection Refused". The Let's Debug test from its own server gets same No Route error (while Staging reports something different).
Have you tried disabling that firewall-cmd system completely? If so and your EC2 Security Group is correct then check your AWS VPC
This is sort of routine comms config and not related to Let's Encrypt directly. Anyone trying to connect to your domain would fail. We often help with these basics but you may need to consult with AWS support. Or, whoever provided the instructions you are following.
Use https://letsdebug.net to test your connection. Or even a machine other than that EC2 instance (so not curl from ssh). Like try a mobile phone with wifi disabled to use your carrier network (or even with wifi on for that matter since we're testing a connection to AWS)
That means you should consult with AWS support or whoever has provided your config instructions We sort of cross-posted. We're not an all-purpose support site.
AWS is a complex service which can have a steep learning curve. Their docs are often helpful. Perhaps it is not the right service for you. There are many hosting options. Perhaps choose one that provides exactly what you need "out of the box" rather than having to DIY every bit.