pymysql.err.OperationalError: (2003, "Can't connect to MySQL server on 'localhost' ([WinError 10061] 由于目标计算机积极拒绝，无法连接。)")

This error message indicates that there is a problem connecting to the MySQL server running on the local machine. This could be due to a number of reasons, such as:

- The MySQL server is not running or has been stopped.
- The MySQL server is running on a different port or IP address than the one specified in the connection settings.
- There is a firewall or network configuration issue preventing the connection.

To resolve this error, you should try the following steps:

1. Ensure that the MySQL server is running and listening on the correct IP address and port.
2. Check that the connection settings in your code are correct and match the server settings.
3. Check for any firewall or network configuration issues that may be blocking the connection.
4. Try connecting to the MySQL server from a different machine to see if the issue is specific to the local machine.

If you are still unable to connect to the MySQL server, you may need to seek further assistance from a database administrator or IT support staff.