Symptom

 When attempting to connect to an Amazon S3 (and possibly other) cloud storage location, the Integration Builder throws the following error:

Environment

 BarTender Integrations

Amazon S3

Fix/Answer

When working with Cloud Storage accounts, you'll need to set one up first within BarTender. This is a local account stored within the System Database. Follow this article on how to set up an S3 storage account: How to set up an Amazon S3 storage location for Integrations 

In addition to storage accounts, the user may be setting up the scan folder URL incorrectly. See the same article with how to properly set this up.