The problem seems to be that the DNS zone is named "www.niwdedev.me" instead of "niwdedev.me". So, for example, http://niwdedev.me/ doesn't resolve because the DNS servers don't think it exists. On the other hand, you created an A record named www in the zone, so http://www.www.niwdedev.me/ does currently exist!
You have to fix it by renaming the zone from "www.niwdedev.me" to "niwdedev.me" in the DNS control panel, if that's possible. If it's not possible, you might have to create a new zone named "niwdedev.me" and copy your records over, and you might have to delete the old one.
For Let's Encrypt, you can work around the problem by creating the CAA record mentioned.
That should be letsencrypt.org -- you added a second y.
The end result is that the record needs to be named www.niwdedev.me. Do you know what you need to enter to produce that? You probably have to leave the host field blank, or write @ or something.