Import another .jar library

My plugin is dependent on another library/plugin. I added the library .jar file into Project Structure... | Libraries. And the library is visible in Intellij editor. But when I debug my code it throws the exception: Caused by: java.lang.ClassNotFoundException: <my imported class reference path> PluginClassLoader[<my plugin name/id>] com.intellij.ide.plugins.cl.PluginClassLoader@74a5ac98. How can I link that another library/plugin to my own plugin? The path to that another plugin is <my user windows 10 path>\.IntelliJIdea2019.3\config\plugins\<another plugin dir>