Plugin 'DBN' failed to initialize and will be disabled

I just restarted Pycharm after installing DBN plugin under the version 2021.2.2 , and I am so sure DBN was installed in PyCharm successfully. 

but I now get the following error:

Caused by: java.lang.ClassNotFoundException: org.apache.poi.ss.usermodel.Workbook PluginClassLoader(plugin=PluginDescriptor(name=Database Navigator, id=DBN, descriptorPath=plugin.xml, path=~\AppData\Roaming\JetBrains\PyCharmCE2021.2\plugins\dbn.jar, version=3.3.1555.0, package=null)

Everything I can do for this?

For your information, it may be caused by my corporate web gateway? im not sure. I can't even connect to marketplace in Pycharm. This Plugin 'DBN' Database Navigation was downloaded from JETBRAINS. and installed it into Pucharm from Disk.