I have a Nintex site workflow that does a query of an employee list (id's saved into a collection variable) - then processes through a for each loop (each item in the collection) and confirms that the person's manager is a 'valid SharePoint user'. Within the for each is also an update of the list item. I have workflow logging messages on most of the steps in the workflow. From these log messages I can tell the process seems to work fine, however after the last collection item is processed the workflow seems to hang (based on time stamp of log messages) for about 4 minutes and then errors out with basic log message 'An error has occurred in ... " (no useful details). I looked in SharePoint ULS log and found nothing. I am not sure how to proceed with debugging this error - any help is appriciated! Thanks.