I have used the Nextcloud and Let’s Encrypt containers, I have namecheap as a dns and the ddns set up in my ASUS Merlin router.
Errors I get are:
Challenge failed for domain
DNS problem: NXDOMAIN looking up A for mydomain
No valid IP addresses found for myddns
Timeout during connect (likely firewall problem)
I’ve got the cname in namecheap, port forwarded in router, config instructions have been followed for nextcloud, adding the overwrite_url stuff.