We have any problems with download Magento 2 composer modules on CircleCI. Apparently an network error. This error is intermittent, when use rebuild option sometimes happens sometimes not.
Error examples:
Error response from daemon: invalid registry endpoint. Unable to ping registry endpoint 279726348302.dkr.ecr.us-east-1.amazonaws.com/v0/
v2 ping attempt failed with error: dial tcp: lookup 279726348302.dkr.ecr.us-east-1.amazonaws.com on 172.17.220.1:53: dial udp 172.17.220.1:53: connect: network is unreachable