PyMySQL Connection Failed: Cannot Connect to PlanetScale Database Server

[SilentSailing34]

I’m having trouble connecting to my PlanetScale database from a Windows machine using PyMySQL. The connection works fine on Mac but fails on Windows with error 2003.

I’ve already checked these things:

• Database exists and credentials are correct
• Using SSL connection as required
• Network tests pass (can ping the server on port 3306)
• DNS lookup works properly
• Tried different networks including mobile hotspot

The error message isn’t very helpful and I can’t figure out what’s different between the Mac and Windows environments. Has anyone encountered this before?

[neonNautilus]

Windows environments can be tricky with PyMySQL connections. I’ve seen this exact issue where Mac works but Windows throws error 2003.

Usually it’s Windows blocking the SSL handshake or using different certificate validation. Try adding ssl_disabled=True temporarily to see if that’s the culprit. Also check if Windows Defender or corporate firewall is interfering.

But honestly, dealing with PyMySQL quirks across different OS environments gets old fast. I stopped wrestling with these connection issues years ago.

Instead of debugging PyMySQL on Windows, I’d automate the database operations through Latenode. You can set up workflows that handle all the database connections server-side, so your local environment doesn’t matter. Plus you get retry logic, error handling, and monitoring built in.

I use this approach for all my database integrations now. No more “works on my machine” problems when the database logic runs in the cloud.

Latenode - Create AI Agents & Autonomous Workflows | No-Code &...

[TomDream42]

The Problem:

You’re having trouble connecting to your PlanetScale database from a Windows machine using PyMySQL, while the connection works fine on a Mac. The error you’re receiving is error 2003, which isn’t very informative. You’ve already ruled out several common causes, including incorrect credentials, network issues, and DNS problems.

Understanding the “Why” (The Root Cause):

The discrepancy between your Mac and Windows environments points to an issue with how PyMySQL interacts with the operating system’s handling of SSL certificates and socket connections. Windows and macOS handle SSL certificate verification and socket timeouts differently. PyMySQL’s default settings may not be optimal for Windows’s networking stack, leading to connection failures. Furthermore, Windows Defender or corporate firewalls might interfere with the SSL handshake. Different Python versions or installation methods (like using conda vs. pip) might also impact SSL library compatibility. Finally, using incorrect path separators in your SSL certificate path on Windows can cause problems.

Step-by-Step Guide:

1. Verify and Adjust PyMySQL Connection Parameters: The most likely culprit is how PyMySQL interacts with your Windows environment. Modify your PyMySQL connection string to explicitly handle SSL and timeout settings. Add or modify these parameters as necessary:

import pymysql

mydb = pymysql.connect(
  host="your_planetscale_host",
  user="your_username",
  password="your_password",
  database="your_database_name",
  ssl_ca=None,  # Bypass certificate verification (use cautiously!)
  ssl_verify_cert=False, # Bypass certificate verification (use cautiously!)
  charset='utf8mb4', # Ensure UTF-8mb4 character set
  connect_timeout=60, # Increase connection timeout
  read_timeout=60     # Increase read timeout
)

Important Considerations: Setting ssl_ca=None and ssl_verify_cert=False disables SSL certificate verification. This should only be used for debugging purposes and must be re-enabled in production for security. If you continue to have issues, investigate your certificates and their paths on the Windows system.

2. Check for Firewall Interference: Windows Defender or a corporate firewall might be blocking your database connection attempts. Temporarily disable your firewall or add an exception for your database port (3306) to see if this resolves the issue. If it does, configure your firewall to allow traffic on port 3306.

3. Examine the SSL Certificate Path: Ensure that the path to your SSL certificate in your PyMySQL connection string uses forward slashes (/) as path separators, not backslashes (\), which is standard for Windows systems.

4. Update PyMySQL: Make sure you’re using the latest version of PyMySQL. Older versions contained known bugs affecting Windows compatibility. Run pip install --upgrade PyMySQL to upgrade to the latest version.

5. Consider an Alternative Driver (mysql-connector-python): If the issues persist, try switching to the official MySQL Connector/Python. It sometimes provides better Windows compatibility than PyMySQL.

Common Pitfalls & What to Check Next:

• Proxy or VPN: If you’re behind a corporate proxy or VPN, it might be interfering with the connection. Try connecting from outside the proxy/VPN.
• Python Version and Installation: Different Python versions (e.g., Python 3.7 vs. 3.10) and installation methods (conda vs. python.org installer) can influence SSL library behavior. Try using a different Python environment or version.
• Incorrect host value: Double-check that you have the correct host name or IP address for your PlanetScale database.
• Incorrect Character Set: Ensure the character set in your connection string matches the database’s character set.

Still running into issues? Share your (sanitized) config files, the exact command you ran, and any other relevant details. The community is here to help!

[SwiftCoder42]

This bug is super frustrating - it’s platform-specific and the error message tells you nothing useful. I hit something similar deploying a Django app with PlanetScale. Windows and Mac handle SSL certificate chains differently, which causes this mess. Windows often chokes on certificate verification with cloud databases. Add ssl_ca=None and ssl_verify_cert=False to your PyMySQL connection params. This skips the Windows certificate store issues that silently kill connections. Check your Python setup too. Different Python versions or package managers can mess with SSL libraries. I’ve seen conda Python act totally different from python.org installs on Windows. Also - any antivirus with real-time protection? Sometimes they scan outbound database connections and break the handshake.

[Oscar64]

Error 2003 on Windows usually happens because PyMySQL handles socket connections differently than Unix systems. Had this exact problem last year - my data pipeline worked fine on macOS but crashed on Windows servers. Turns out the connection timeout was too aggressive for Windows TCP stack. PyMySQL’s defaults don’t play nice with Windows networking. Set connect_timeout=60 and read_timeout=60 in your connection params. Also check you’re using the latest PyMySQL - older versions had Windows bugs. Here’s a Windows-specific gotcha: certificate store handling. Even with SSL disabled for testing, Windows still messes with connection setup. Make sure you’re not behind a corporate proxy or VPN that’s silently breaking the connection.