vapor: Vapor cloud deploy failed: Sockets Error: Failed trying to connect to http://redis.eu.vapor.cloud:6379

• Vapor Version: 2.4.2
• OS: macOS High Sierra
• OS Version: 10.13.3
• Vapor Toolbox Version: 3.1.3

I setup Vapor project manually with swift package manager. I follow the documentation. It build and runs successfully in my local machine, both for debug and release build.

But it failed to deploy to vapor cloud:

    ....
    ....
    env: development
    db: none
    replicas: 1
    replica size: free
    branch: development
    build: clean
    Creating deployment [Done]
    Connecting to build logs ...
    Waiting in Queue [Failed]
    Error: Sockets Error: Failed trying to connect to http://redis.eu.vapor.cloud:6379
    
    Identifier: Sockets.SocketsError.connectFailed
    
    Here are some possible causes: 
    - The hostname or port is not valid    

Anyone knows what caused this error?

SO thread.