Solution
This issue could be caused by missing Windows User-permissions. If an Operator has not the permissions to read&execute inside the folder where the Userinterface is located, this issue could occur. If this is the reason, then you can solve the issue by giving the Operator permissions to read&execute inside the directory where the folders and files of the deployment are placed.
Here I linked you how to change the folder and file permissions on a Windows 10 System.