The MySQL server is not running: Make sure the MySQL server has been started.
Incorrect IP address or port: Make sure that the IP address and port number entered are correct.
Firewall configuration: Ensure that the firewall allows connection to the IP address and port number of the MySQL server.
There is an error in the MySQL server configuration file: Check the configuration file of the MySQL server to ensure the correct IP address and port number are set.
Login credentials are incorrect: please verify that the username and password are correct.
Permission issues with the database: Ensure that users have permission to connect to the specified database.
Ensure that the version of Navicat you are using is compatible with the version of the MySQL server.
If the MySQL server is overloaded, it may not be able to accept new connections.
Check the internet connection to ensure that it is working properly and can connect to the MySQL server.
Other issues such as incorrect MySQL server configuration, network settings, or other factors may also prevent a successful connection.
