I created 2 different vpc’s (one for front end and one for backend) and of course the subnets are in different regions. There is no overlap. I was able to configure most of the things asked in the challenge but having trouble on one of them. where the backend instances are not able to ping within themselves.
Two different VPCs? Do you mean that you are peering them? Is this the same scenario as your other question, or a different one?