I have a similar issue.
Unable to issue LetsEncrypt certificate for site summerville_org because it has external DNS and external A/AAAA records.
Unable to issue LetsEncrypt certificate for site summerville_net because it has external DNS and external A/AAAA records.
I redirected the DNS servers on my Hover account to point to the ones listed in the support documentation.
I've checked with some DNS checking sites and they are all showing the following server: 188.8.131.52, which is my vps server's IP address.
I deleted the sites from the old hosting service (Host Gator) and made sure that there were no additional A records on Hover.
So, is it just a wait and see sort of thing and try again in an hour?