Symptoms
You run the Response Group Agent Live resource kit tool and experience a network outage in a Microsoft Skype for Business Server 2015 environment. The tool creates multiple error dialog boxes that state "Error retrieving groups. Do you want to retry?". It's expected that only one error dialog box can be generated in this scenario.
Resolution
To fix this issue, install the cumulative update 6.0.9319.548 for Skype for Business Server 2015 Resource Kit Tools: May 2019.