Please update the used MySQL Connector version from currently used 5.1.38 (release on 2015-12-07 ) (./plugins/com.mysql.jdbc_5.1.38.jar) to at least 5.1.46, but much better to active branch 8.0.15
Why is that update required?
I migrated my MySQL DB to latest 8.0.x and default password handling was changed.
This required the client to know that new
caching_sha2_password authentication plugin for MySQL 8.0.
But since the 5.1.x branch is not longer the active branch, please update directly to MySQL Connector 8.0.15
Security downgrade by adding DB user with mysql_native_password is no option
CREATE USER 'account'@'localhost' IDENTIFIED WITH mysql_native_password BY 'pass123';
After I removed the ./plugins/com.mysql.jdbc_5.1.38.jar from Katalon installation and placed the mysql-connector-java-8.0.15.jar there I’m able to connect to my DB again without getting
java.sql.SQLException: Unable to load authentication plugin 'caching_sha2_password'