Consider the following scenario:
You have a Skype for Business Front End pool that has many response group workflows.
You try to create or edit a response group workflow from the Skype for Business Server 2015 Control Panel.
In this situation, the configuration page can't load and you receive a "Response Group Configuration Tool Failure" error message.
This issue occurs because the configuration page runs cmdlets to retrieve workflow data. If the Front End server pool has too many response group workflows, the retrieve request will have a time-out.
To fix this issue, install the July 2018 cumulative update 6.0.9319.534 for Skype for Business Server 2015, Web Components Server.