Does Dynadot offer support for Automatic Certificate Management Environment?
On LetsEncrypt.org they write the following about Automatic Certificate Management Environment:
The best way to use Lets Encrypt without shell access is by using built-in support from your hosting provider. If your hosting provider offers Lets Encrypt support, they can request a free certificate on your behalf, install it, and keep it up-to-date automatically. For some hosting providers, this is a configuration setting you need to turn on. Other providers automatically request and install certificates for all their customers.
Check our list of hosting providers to see if yours is on it. If so, follow their documentation to set up your Lets Encrypt certificate.
If your hosting provider does not support Lets Encrypt, you can contact them to request support. We do our best to make it very easy to add Lets Encrypt support, and providers are often happy to hear suggestions from customers!
Stupid answer, to request a wildcard certificate an API access to the DNS provider is necessary. So it is definitely not a question for the hosting provider, dynadot had to provide this.