I encountered the same error while connecting to Derby 10 database as a datasource.
To overcome this, you could navigate to "Administration > Server Configuration > Embedded Derby server configuration" and turn on "**Enable Remote Access**".
Or, you could execute the following property in the VQL Shell,
Once done, you’ll be able to successfully connect to Derby 10 database.
If you require further assistance and if you are a valid support user, you could create a support case on Denodo Support Site so that our team will assist you.
Hope this helps!