During import of file, received “invalid database instance”.

Symptoms
The XML ExportLog displays:"com.primavera.common.exceptions.InvalidAuthenticationModeException: Invalid database instance. This can be caused by specifying an invalid database instance string or by specifying a database instance that connects to a database intended to be used with a different version of this product."

Cause
Changes were made to the Admin Tool such that Authentication mode did not match the settings of the database.
Solution
Log into the Primavera Admin Tool - C:\Program Files\Common Files\Primavera Common\Java\admin
Check the Authentication modes at:
- Cutom\INTENAL_PLUGINS\Authentication
- Custom\Primavera P6v7 Configuration\Authentication
These need to be set to the same mode that matches the database.