Hi there,
You may need to do some further configuration with your router such as configuring your router to accept outside traffic. If you have enabled remote access inside of Sighthound Video and have verified that using the "Local," and "Internal" address works, then you can continue with the "External" configuration. Also, you'll want to check that in Sighthound Video in the remote access menu you have "Open this port in my router" checked.
If everything from above is working, then I recommend following the instruction from the following link to see if you correctly configure the port forward rule.
https://support.google.com/wifi/answer/6274503?hl=enThe IP address you'll specify while creating this rule is the IP address of the computer running Sighthound Video. The port is the port number that you specified when configuring remote access in Sighthound Video by default this is port 8848.