nixops is stuck due to cache.nixos.org

gistfile1.txt

$ nixops deploy -d simplest                                                                                                                                  
my-key-pair> uploading EC2 key pair ‘charon-xxx’...
testnginx..> creating EC2 instance (AMI ‘ami-xxx’, type ‘t2.micro’, region ‘us-east-1’)...
testnginx..> starting EC2 instance in zone ‘us-east-1a’ due to volume ‘vol-xxx’
testnginx..> waiting for IP address... [pending] [pending] [pending] [pending] [pending] [pending] [running] None / 10.100.1.28
testnginx..> waiting for SSH..........................
testnginx..> replacing temporary host key...
testnginx..> attaching volume ‘vol-xxx’ as ‘/dev/xvdf’... [attaching] [attached] 
testnginx..> setting state version to 17.09
building all machine configurations...
these derivations will be built:
  /nix/store/6ad5xq35dia3yp5zppdvbz99zsf00fss-etc-hosts.drv
  /nix/store/6swih7py2in56ykjmrk22k5bn5b43gqr-etc-ssh_known_hosts.drv
  /nix/store/qjjbfixfhj0mv160gxfr1j2c257gicgx-unit-nscd.service.drv
  /nix/store/x0qxpsi1jmvl7i0vg1bb062rcnagmnhz-system-units.drv
  /nix/store/qzhzclxhlr0n6ppg53i4zj0c64wjvn07-etc.drv
  /nix/store/ic7klv2m97mg8kdidf2dckxmgicbvicn-nixos-system-testnginx-18.03.git.846b5c4.drv
  /nix/store/rf3k9m0l1hii8xkys9n9vn196f5gz24k-nixops-machines.drv
building path(s) ‘/nix/store/lavi7ppy4lbif0wvs52kwcvn6qf3c5wn-etc-hosts’
building path(s) ‘/nix/store/7hld75zj0cqd8vm34mvq01m5xnny62z2-etc-ssh_known_hosts’
building path(s) ‘/nix/store/0s5b7zn9a3yqv0xy1q699q4nxw6lyhgl-unit-nscd.service’
building path(s) ‘/nix/store/43zzqpvq880pm7lirm162vgisnhr0cqs-system-units’
building path(s) ‘/nix/store/3dgca7vsns0z5y9mcbs67vjgv1dcnjz5-etc’
building path(s) ‘/nix/store/x4m75x6w09fb7bz6mkk4r0yd9591m758-nixos-system-testnginx-18.03.git.846b5c4’
building path(s) ‘/nix/store/qbzpz1jmv87fw77mdl36gcdsv4x416nj-nixops-machines’
testnginx..> copying closure...
testnginx..> download-from-binary-cache.pl: still waiting for ‘https://cache.nixos.org/nix-cache-info’ after 5 seconds...