I'm attempting to scp to an EC2 inside a VPC and getting timed out.

Established facts:

1. I can ssh into the VPC itself - the keypair works and the instance subnet is open to the internet.
2. The folder I'm attempting to transfer to on the EC2 has permissions 700
3. The command I'm running is: scp -i mykey.pem dumbtest.txt ubuntu@ec2-<my-ip>.compute-1.amazonaws.com:/home/ubuntu

Are there additional steps I need to take to scp into EC2's on a VPC?