VS403093: The work item XXXXX cannot be moved. Work items with links to Test Case work items cannot be moved.
Issue: VS403093: The work item XXXXX cannot be moved. Work items with links to Test Case work items cannot be moved. Please remove the work item link(s) and try again
Solution : This occurs only when a workitem is linked with TestCases. The only solution is to remove the links and move the workitems again and as per Microsoft this is working as designed. Even if you want to change the workitem type this issue with occur, so remove the link and change the workitem type, then again link in with the TestCase.
Incase if you want to remove lot of links from TestCases, use the API call and store the links in a Database, then remove the links & then again move the workitems. After moving the workitems again link the TestCases with the workitems.