When you get to step 6 (create connection), it does not work - the UI validation complains the peer CIDR must not overlap with the VPC address prefix (which was configured in step 2).
To get around this I had to delete the address prefix (i.e. revert step 2), perform step 6, and then recreate the address prefix (repeat step 2).
When you get to step 6 (create connection), it does not work - the UI validation complains the peer CIDR must not overlap with the VPC address prefix (which was configured in step 2). To get around this I had to delete the address prefix (i.e. revert step 2), perform step 6, and then recreate the address prefix (repeat step 2).