I had the exact same problem. I tried to connect the SLAM dunk to a computer but it didn't solve the problem. I think the error might come from the ip adress of the slam dunk because when using the computer, after the following command:
rviz is still unable to locate the master. And I couldn't access the internet either, even when connected by Ethernet cable, that's why an IP issue would be my guess.
I have unfortunately no solution, two days later my SLAM dunk gave me a "starting heat management [fail]" at boot and has been at the post-sale customer service since then...