Connecting to MySQL may result in various errors. See below for some of the most common.

The solutions are based on that at least DbVisualizer 12.1.3 is used. Use Help->Check for Update in DbVisualizer or download from

Problem 1:

"The last packet successfully received from the server was 1 milliseconds ago. The last packet sent successfully to the server was 1 milliseconds ago.":

Solution 1:

If your connection is using Settings Format = Server Info:

  1. Open the Properties tab for your MySQL connection
  2. Select Driver Properties
  3. Locate the useSSL property and set its value to false (make sure the edited check mark is enabled)
  4. Click Apply
  5. Connect

If your connection is using Settings Format = Database URL:

  1. In the Database URL field add ?useSSL=false last (or &useSSL=false if there are parameters already in the URL)
  2. Connect

Problem 2:
"Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification."

Solution 2:
According to the error you have three options
  1. Set the Driver property useSSL to false. The driver does report false as the default value but it may be set to true based on certain conditions on the server. I.e. you will need to set it explicitly to false.  
  2. Set the Driver property verifyServerCertificate to false. This will, from my understanding, connect using SSL but will not verify the servers certificate. 
  3. Provide a truststore for the server certificate verification.

Driver Properties are set in the Connection Properties for your connection. For information regarding setting up truststores please see the the solution article MySQL: Connecting securely to a MySQL server for details. 
Note that this article is written with the MySQL driver version 8 in mind.
The following MySQL article provides related information for MySQL driver 5.