Something is definitely wrong with your network setup.
The 174.21.130.19 IP address is an external IP address. For an example, I see you have ports 6700-6751 forwarded to 192.168.0.11, so the internal IP address of your Tablo should be 192.168.0.xx
What device is the 192.168.0.11 IP?
Have you placed the Tablo in the DMZ? Check the “DMZ hosting” page.