yarn workspace server start: command not found

When I remove deploy section from fly.toml competely, I get this error

Updating existing machines in 'new-app765' with rolling strategy
  [1/1] Waiting for 6e82d922f01098 [app] to become healthy: 0/1

WARNING The app is listening on the incorrect address and will not be reachable by fly-proxy.
Make sure your app is listening on the following addresses:
  - 0.0.0.0:8080
Found these processes inside the machine with open listening sockets:
  PROCESS        | ADDRESSES                             
-----------------*---------------------------------------
  /.fly/hallpass | [fdaa:2:2220:a7b:141:daea:1f87:2]:22  

Error: timeout reached waiting for healthchecks to pass for machine 6e82d922f01098 failed to get VM 6e82d922f01098: Get "https://api.machines.dev/v1/apps/new-app765/machines/6e82d922f01098": net/http: request canceled