The following error is displayed after clicking on the "Synchronize Groups" button in the K2 for SharePoint app:
"Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index"
Manually executing the "Refresh SharePoint Group Identity" of the "SharePoint_Integration_Workflow_Helper_Methods" SmartObject results in the same error.
To resolve this please log a support ticket and request a tool that will be used to refresh the SharePoint Integration SmartObject. This will refresh "SharePoint_Integration_Workflow_Helper_Methods." After this you should be able to use the "Synchronize Groups" feature with no issues.
The tool must only be used under the guidance of the support engineer.