Python 3.13 Login Failed Connection Refused Fix [Solved] ...

Issue	Primary Cause	Quick Fix
Connection Refused	IPv4 vs IPv6 localhost binding mismatch	Use 127.0.0.1 instead of ‘localhost’
Login Failed	Deprecated SSL/TLS versions in 3.13	Update urllib3 and certifi packages
Socket Error	Firewall blocking new Python binary	Allow Python 3.13 through system firewall

Table of Contents

What is the Python 3.13 Login Failed Connection Refused Error?

The Python 3.13 “Login Failed: Connection Refused” error typically occurs when a script attempts to connect to a local or remote service—such as a database or an API—and the handshake is rejected.

Python 3.13 introduced stricter enforcement of network protocols and internal changes to how the socket and ssl modules handle connections. These updates can break older authentication scripts.

This error often surfaces during database logins (PostgreSQL, MySQL) or when using libraries like requests or httpx to hit local development servers.

Step-by-Step Solutions

1. Fix Localhost Binding Issues

Python 3.13 may prioritize IPv6 (::1) over IPv4 (127.0.0.1). If your service is only listening on IPv4, the connection will be refused.

Update your connection string from “localhost” to the explicit IPv4 address:

# Change this:
DB_HOST="localhost"

# To this:
DB_HOST="127.0.0.1"

2. Upgrade Core Networking Packages

Older versions of urllib3 and requests may not be fully compatible with Python 3.13’s new C-API. Ensure your environment is up to date.

pip install --upgrade pip setuptools wheel
pip install --upgrade urllib3 requests certifi

3. Handle TLS/SSL Compatibility

Python 3.13 has deprecated several insecure TLS versions. If the server you are logging into uses old protocols, Python will refuse the connection.

You can verify your current SSL version and certificates using this command:

python3.13 -m ssl

If the remote server is outdated, you may need to create a custom SSL context that allows older TLS versions, though upgrading the server is recommended.

4. Verify Firewall and Binary Permissions

Since Python 3.13 is a new installation path, your OS firewall (like Windows Defender or macOS LuLu) may see it as an untrusted application.

Check if the Python 3.13 binary has permission to access the network. On Linux/macOS, ensure the port isn’t being held by a zombie process from a previous Python version:

# Find process using port 8000 (example)
lsof -i :8000
# Kill the process
kill -9 [PID]

5. Update Database Drivers

If the “Login Failed” error occurs specifically with databases like PostgreSQL or MySQL, update the specific driver. Drivers compiled for 3.12 may fail on 3.13.

pip install --upgrade psycopg2-binary mysql-connector-python