500 or 423 code resulted when try to upgrade the database

Issue

• 500 or 423 code resulted when try to upgrade the database

The following is an image with this error code 500.

• Message "Error: connect ECONNREFUSED"is shown when try to get access to the MBaaS.

The following is an example of this error message.

Service unavailable, check service exists and is running ok - { [Error: connect ECONNREFUSED 10.0.0.1:8204]
  code: 'ECONNREFUSED',
  errno: 'ECONNREFUSED',
  syscall: 'connect',
  address: '10.0.0.1,
  port: 8204 }

• Message "Failed to start App - App db migration is in progress" is shown when try to start the application.
• upgrade database fails with error message: "Unexpected Status Code 500"
• Message Unexpected Status Code 423 is found after try to upgrade the database as following.

21-03-2017 3:12:46:  Checking user API key
21-03-2017 3:12:46:  Stopping app and creating new db for app
Unexpected Status Code 423

• Can't upgrade database using Data Browser
• Upgrade database stuck