MySQL server is not running on the target host. Firewall or network security group blocks port 3306 between the client and server. Wrong hostname or IP address configured in the connection string. MySQL is bound to 127.0.0.1 only (bind-address in my.cnf) and remote connections are attempted

Step 1: Verify MySQL is running on the server: `systemctl status mysql` or `ps aux | grep mysqld`.. Step 2: Check MySQL is listening on the correct interface: `netstat -tlnp | grep 3306`.. Step 3: Open the firewall port: `sudo ufw allow 3306/tcp` or add an inbound rule in Azure NSG / AWS Security Group.. Step 4: If MySQL is bound to localhost only, set `bind-address = 0.0.0.0` in `my.cnf` under `[mysqld]` and restart.

Critical severityconnection

Power BI Refresh Error:
2003

What does this error mean?

The client cannot reach the MySQL server — typically a network, firewall, or wrong host/port issue.

Common causes

1MySQL server is not running on the target host
2Firewall or network security group blocks port 3306 between the client and server
3Wrong hostname or IP address configured in the connection string
4MySQL is bound to 127.0.0.1 only (bind-address in my.cnf) and remote connections are attempted

How to fix it

1Step 1: Verify MySQL is running on the server: `systemctl status mysql` or `ps aux | grep mysqld`.
2Step 2: Check MySQL is listening on the correct interface: `netstat -tlnp | grep 3306`.
3Step 3: Open the firewall port: `sudo ufw allow 3306/tcp` or add an inbound rule in Azure NSG / AWS Security Group.
4Step 4: If MySQL is bound to localhost only, set `bind-address = 0.0.0.0` in `my.cnf` under `[mysqld]` and restart.

Frequently asked questions

How do I test MySQL connectivity from an ADF self-hosted integration runtime?

On the integration runtime machine, run `telnet <mysql-host> 3306` or `Test-NetConnection -ComputerName <mysql-host> -Port 3306` in PowerShell to verify network reachability.

MySQL is running but I still get error 2003 — why?

MySQL may be bound to 127.0.0.1 only. Check `bind-address` in my.cnf and ensure it is set to `0.0.0.0` or the specific server IP to allow remote connections.

Can MetricSign alert me when this connectivity issue breaks a pipeline?

Yes — MetricSign triggers a pipeline_failed incident when ADF cannot reach the MySQL source, giving your team immediate visibility.

Official documentation: https://dev.mysql.com/doc/mysql-errors/8.0/en/server-error-reference.html