Federation tutorial gives an error

I got most of the tutorial - subgraph creation, publishing subgraphs to the studio, setting up the router - up and running just fine.

When I try to run a unified query on the supergraph, however, I get the following error,

2022-11-10T19:20:59.880454Z apollo-router/src/services/subgraph_service.rs:173 ERROR [trace_id=dc031984b0655a46580ce9ac8c7fd6e6] apollo_router::services::subgraph_service: fetch_error="hyper::Error(Connect, ConnectError(\"dns error\", Custom { kind: Uncategorized, error: \"failed to lookup address information: nodename nor servname provided, or not known\" }))"
2022-11-10T19:20:59.880537Z apollo-router/src/plugins/include_subgraph_errors.rs:67  INFO [trace_id=dc031984b0655a46580ce9ac8c7fd6e6] apollo_router::plugins::include_subgraph_errors: redacted subgraph(locations) error
2022-11-10T19:20:59.880566Z apollo-router/src/query_planner/execution.rs:188 ERROR [trace_id=dc031984b0655a46580ce9ac8c7fd6e6] apollo_router::query_planner::execution: Fetch error: HTTP fetch failed from 'locations': HTTP fetch failed from 'redacted': redacted

PS: I have both subgraph servers running and can query these individually via Apollo studio.