Can not connect to the database server: can't connect to mysql server on example.com (10061)

Symptoms

• Can not connect to the database server, the following error is shown:

  failed to connect to mysql at example.com:3306 with user admin can't connect to mysql server on example.com (10061)

• Port 3306 is closed:

  # nmap example.com -p 3306
  PORT STATE SERVICE
  3306/tcp closed mysql

  # nc -zv 177.47.183.60 3306
  Ncat: Version 7.92 ( https://nmap.org/ncat )
  Ncat: Connection refused.

Cause

Error 10061 indicates that network connection has been refused.

Port 3306 is closed.

Resolution

Contact server/network administrator to open port 3306.