This is exactly why I didn't want the client to use this router. 14 days later and no one can even answer a simple question.
It turned out to be that there was a web interface setup on port 0 at 10.10.10.1 (in case anyone else is also wondering).
I am sorry that someone in the community was not able to respond to your question sooner. Typically our Quick Start Guide for our Business CPE products does include instructions on Accessing the GUI but that section appears to have been omitted from the NetVanta 3140 Quick Start Guide. I apologize for your confusion on not finding that information in this guide and I will work with our documentation team on updating these instructions.
I do encourage you to also open a Product Support ticket in the future if you do need further assistance after using the Support Community and we will be happy to help answer any technical questions or provide troubleshooting assistance. This guide below will help with instructions on opening a Support ticket.
ADTRAN Product Support Manager - Business CPE