acme.messages.Error: urn:ietf:params:acme:error:invalidEmail :: The provided email for a registration was invalid :: Error creating new account :: “XYZ” is not a valid e-mail address
In my case, I created Virtual Server without the email feature enabled. Hence when Webmin tried to generate Let’s Encrypt SSL Certificate, it used the default email address. As Virtual Server did not have a valid email address, it created email using the username and host name.
For example, if my Virtual Server admin username is “abc” and my droplet host name is “droplet1”, Webmin tried to get certificate with email “abc@droplet1” (note that there is no “.com” suffix)
As this email is invalid, above error is thrown.
Instead of using the email generated by Webmin, explicitly provide admin email address. Go to VirtualMin > Select your domain > Edit Virtual Server > Configurable Settings > Contact Email > Select another radio button and provide your email address > Click “Save Virtual Server”. Now try to generate SSL certificate. It will use your explicitly provided email address and successfully generate SSL certificate.