Python Flask Website DB Connection Problem

Answered

ümit öztürk

• August 09, 2025 09:29

Hi everyone,

I'm facing a very specific and persistent database connection issue with a Python Flask application running on cPanel, and I'm hoping to get some insight from the community.

Problem Summary: My Flask application, configured via "Setup Python App," is unable to connect to the MySQL database on localhost. The application fails with a [Errno 111] Connection refused error.

Crucial Observation (The Contradiction): To rule out credential or service issues, I created a simple PHP script with the exact same database credentials, and it connects to the database on localhost without any problems.

This tells me:

1. The MySQL service is running.

2. My database username, password, and database name are all correct.

3. The host address localhost is valid for PHP applications on this server.

Technical Details:

• Application: Flask 3.0.3, Python 3.7.17 (downgraded for compatibility).

• Database Connector: PyMySQL==1.1.1

• Cpanel App Root: /home/myuser/pump-calculation

• DB_CONFIG in app.py:

  DB_CONFIG = {
      "host": "localhost",
      "user": "tmxflow1_progadm",
      "password": "my_correct_password",
      "database": "tmxflow1_program",
  }
  
  

The Exact Error Message: The error from my Flask app's log file is: (2003, "Can't connect to MySQL server on 'localhost' ([Errno 111] Connection refused)")

Attempts Made:

• Confirmed localhost is the correct host for PHP, and the user has ALL PRIVILEGES on the database.

• The passenger_wsgi.py is configured with the standard from app import app as application line.

• I have tried restarting and even stopping/starting the Python application multiple times after each change.

• All file and folder permissions are set correctly (755 for directories, 644 for files).

My Question: Given that the PHP environment connects successfully to localhost, but the Python environment is getting an [Errno 111] Connection refused error, it seems the Python application's container or a related configuration is preventing it from reaching the MySQL service on localhost.

Could there be a specific Cpanel or Apache/Phusion Passenger configuration that isolates Python applications from the MySQL service? Is there a different internal host address that Python apps must use instead of localhost?

Any help or suggestions on how to debug this server-level issue would be greatly appreciated.

• 

  ümit öztürk

  • August 10, 2025 13:39
  • Edited

  Hello, i found a solution to my problem and i would want to publish it too.

   

  Here is the solution for me :

   

  First enter the database that you are working in and open sql query page and paste that command :
  
  SHOW VARIABLES LIKE 'socket';

  output for me : 

  

   

  put value to DB config section like this :

  DB_CONFIG = {
      "user": "username",
      "password": "password",
      "database": "database",
      "cursorclass": pymysql.cursors.DictCursor,
      "unix_socket": "var/lib/mysql/mysql.sock"
  }

  and voila, that was the fix for me.

   

   

  0
• 

  cPRex Jurassic Moderator

  • August 11, 2025 09:09

  I'm glad you were able to get that working, and thanks for sharing the solution!

  0

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