Huh that's weird. I'm looking at the logs, and this is the first time that's ever happened. It will usually just spit out the following introductory text:
Hi there! Send me your ebooks and I'll send them to your Kindle.
To get started, I'll need you to first tell me your Kindle's email address.
This can be found on your Kindle management page: https://www.amazon.com/gp/digital/fiona/manage?ie=UTF8#pdocSettings
(ending with @kindle.com)