The issue with rpi_null.sh doesn't have to do with a lack of connectivity to our server, it's a bug in the device add experience where it sometimes generates 'null' where there should be instead an invite code for that Pi. I think all of that pinging failing is due to our server configuration -- I'm not aware of any server issues at this time.
Is this on your account that already has devices on it? If so, try deleting the pending Pi entry from the left sidebar, then creating a new Pi install from Add New > Device / Widget > Single Board Computers > Raspberry Pi.
If this is on a different account that has no devices, you'll need to get to the dashboard in order to see the device list so you can delete the pending install that is causing the error. You can do this in a couple of different ways:
The easy solution, if you are comfortable with it: Share your account login and password with me via private message, and I'll add a device and delete the one causing your bug. It will take less than 5 minutes. You can change your password to something you are comfortable sharing with this form.
If you prefer not to share your account, I understand. To resolve the problem yourself, you can create a 'fake' device that will allow you to see the device list and delete the offending entry. To do this, you'll want to follow this documentation until you've completed the 'Connect board to Cayenne' section. At that point you'll be able to see your device list, and you can delete the 'pending' devic(es), which looks like this: