How many validation requests are you seeing? There should be at least 5.
This part of the error message indicates that the primary validation could in fact confirm your control of the domain name, but some of the other (secondary) validations could not.
You can auto-renew if the update to your DNS is automated, to satisfy the new challenge for each renewal. Some DNS providers make that easier than others. There's also a new standard in the works that will allow for setting up a DNS entry once and then just keeping it there, which may make things easier for systems that don't open port 80 worldwide and don't have an easy way to automate updating their DNS records.